Golf Club Heads with Energy Storage Characteristics

ABSTRACT

Embodiments of golf club heads with energy storage characteristics are presented herein. In some embodiments, a golf club head comprises a hollow body comprising a strikeface, a heel region, a toe region opposite the heel region, a sole, a top rail and an inflection point. The inflection point provides increase bending of the strikeface thereby providing performance enhancement over clubs without an inflection point.

CROSS REFERENCE

This is a continuation-in-part of U.S. patent application Ser. No.15/435,054, filed on Feb. 16, 2017, which claims priority to U.S.Provisional Patent Appl. No. 62/295,565, filed Feb. 16, 2016, and U.S.Provisional Patent Appl. No. 62/313,215, Mar. 25, 2016, and is acontinuation-in-part of U.S. patent application Ser. No. 14/920,484,filed on Oct. 22, 2015.

This is also a continuation-in-part of U.S. patent application Ser. No.15/628,639, filed Jun. 20, 2017, which claims priority to U.S.Provisional Patent Appl. No. 62/352,495, filed Jun. 20, 2016, and U.S.Provisional Patent Appl. No. 62/436,019, filed Dec. 19, 2016, and U.S.Provisional Patent Appl. No. 62/462,250, Feb. 22, 2017, and U.S.Provisional Patent Appl. No. 62/484,529, filed Apr. 12, 2017, and whichis a continuation-in-part of U.S. patent application Ser. No.14/920,484, filed Oct. 22, 2015, and which is a continuation-in-part ofU.S. patent application Ser. No. 14/920,480, filed Sep. 15, 2017.

This is also a continuation-in-part of U.S. patent application Ser. No.15/908,427, filed Feb. 28, 2018, which is a continuation-in-part of U.S.patent application Ser. No. 14/920,484, filed Oct. 22, 2015.Furthermore, U.S. patent application Ser. No. 14/920,484, filed on Oct.22, 2015, claims priority to U.S. Provisional Patent Appl. No.62/105,464, filed Jan. 20, 2015, and U.S. Provisional Patent Appl. No.62/206,152, filed Aug. 17, 2015, and U.S. Provisional Patent Appl. No.62/131,739, filed Mar. 11, 2015, and U.S. Provisional Patent Appl. No.62/105,460, filed Jan. 20, 2015, and U.S. Provisional Patent Appl. No.62/068,232, filed Oct. 24, 2014. Also, U.S. patent application Ser. No.14/920,480, filed on Sep. 15, 2017, claims priority to U.S. ProvisionalPatent Appl. No. 62/105,464, filed Jan. 20, 2015, and U.S. ProvisionalPatent Appl. No. 62/206,152, filed Aug. 17, 2015, and U.S. ProvisionalPatent Appl. No. 62/131,739, filed Mar. 11, 2015, and U.S. ProvisionalPatent Appl. No. 62/105,460, filed Jan. 20, 2015, and U.S. ProvisionalPatent Appl. No. 62/068,232, filed Oct. 24, 2014.

This also claims priority to U.S. Provisional Patent Appl. No.62/610,053, filed Dec. 22, 2017. The contents of all of theabove-described disclosures are incorporated fully herein by referencein their entirety.

TECHNICAL FIELD

This disclosure relates generally to golf clubs, and relates moreparticularly to golf club heads with energy storage characteristics.

BACKGROUND

Golf club manufacturers have designed golf club heads to relieve stressin the strikeface of the golf club head. In many instances, thesedesigns do not allow the golf club head to flex in the crown to soledirection. Additionally, these designs may not change where peak bendingof the golf club head occurs and do not allow additional storage ofspring energy in the golf club head due to impact with the golf ball.Additional spring energy can increase ball speed across the strikeface.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate further description of the embodiments, the followingdrawings are provided in which:

FIG. 1 depicts a front, crown-side perspective view of a golf club headaccording to an embodiment;

FIG. 2 depicts the golf club head of FIG. 1 along the cross-sectionalline II-II in FIG. 1;

FIG. 3 depicts a view of a portion of a golf club head that is similarto the golf club head of FIG. 1, along a cross-sectional line similar tothe cross-sectional line II-II in FIG. 1, according to anotherembodiment;

FIG. 4 depicts a view of a portion of a golf club head that is similarto the golf club head of FIG. 1, along a cross-sectional line similar tothe cross-sectional line II-II in FIG. 1, according to anotherembodiment;

FIG. 5 depicts a view of a portion of a golf club head that is similarto the golf club head of FIG. 1, along a cross-sectional line similar tothe cross-sectional line II-II in FIG. 1, according to anotherembodiment;

FIG. 6 depicts a view of another portion of a golf club head that issimilar to the golf club head of FIG. 1, along a cross-sectional linesimilar to the cross-sectional line II-II in FIG. 1, according toanother embodiment;

FIG. 7 depicts a cross-sectional view of a golf club similar to the golfclub head of FIG. 1 along a similar cross-sectional line as thecross-sectional line VII-VII in FIG. 1, according to another embodiment;

FIG. 8 depicts a view of a portion of a golf club head similar to thegolf club head of FIG. 4, according to an embodiment, and a view of thesame area of a standard golf club head;

FIG. 9 depicts a method of manufacturing a golf club head according toan embodiment of a method;

FIG. 10 depicts a back, toe-side perspective view of a golf club headaccording to an embodiment;

FIG. 11 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 10;

FIG. 12 depicts a cross-sectional view of the golf club head of FIG. 10along the cross-sectional line XII-XII of FIG. 10;

FIG. 13 depicts a view of a portion of the golf club head of FIG. 12 anda view of the same area of a standard golf club head;

FIG. 14 depicts a cross-section view of a golf club head, similar to thegolf club head of FIG. 10, along a cross-sectional line similar tocross-sectional line XII-XII of FIG. 10, according to anotherembodiment;

FIG. 15 depicts a back, toe-side perspective view of a golf clubaccording to another embodiment;

FIG. 16 depicts a cross-sectional view of the golf club head of FIG. 15along the cross-sectional line XVI-XVI of FIG. 15;

FIG. 17 depicts a flow diagram illustrating a method of manufacturing agolf club head according to an embodiment of another method;

FIG. 18 depicts a front perspective view of a golf club according toanother embodiment;

FIG. 19 depicts results from testing of the golf club head of FIG. 14,according to another embodiment;

FIG. 20 depicts results from testing of the golf club head of FIG. 14,according to another embodiment;

FIG. 21 depicts a cross sectional view of the golf club head of FIG. 10;

FIG. 22 depicts a back perspective view of a golf club head according toyet another embodiment;

FIG. 23 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 22;

FIG. 24 depicts a cross-sectional view of the golf club head of FIG. 22along the cross-sectional line XXIV-XXIV of FIG. 22;

FIG. 25 depicts a view of a portion of the golf club head of FIG. 24 anda view of the same area of a standard golf club head;

FIG. 26 depicts a simplified cross sectional view of the golf club headof FIG. 22, similar to the detailed cross-sectional view of the golfclub head in FIG. 24;

FIG. 27 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 28 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 27;

FIG. 29 depicts a cross-sectional view of the golf club head of FIG. 27along the cross-sectional line XXIX-XXIX of FIG. 27;

FIG. 30 depicts a view of a portion of the golf club head of FIG. 29 anda view of the same area of a standard golf club head;

FIG. 31 depicts a simplified cross-sectional view of the golf club headof FIG. 27, similar to the detailed cross-sectional view of the golfclub head in FIG. 29;

FIG. 32 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 33 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 32;

FIG. 34 depicts a cross-sectional view of the golf club head of FIG. 32along the cross-sectional line XXXIV-XXXIV of FIG. 32;

FIG. 35 depicts a portion of the golf club head of FIG. 34;

FIG. 36 depicts a simplified cross-sectional view of the golf club headof FIG. 32, similar to the detailed cross-sectional view of the golfclub head in FIG. 34;

FIG. 37 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 38 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 37;

FIG. 39 depicts a cross-sectional view of the golf club head of FIG. 37along the cross-sectional line XXXIX-XXXIX of FIG. 37;

FIG. 40 depicts a portion of the golf club head of FIG. 39;

FIG. 41 depicts a simplified cross-sectional view of the golf club headof FIG. 37, similar to the detailed cross-sectional view of the golfclub head in FIG. 39;

FIG. 42 depicts an interior view of a portion of the golf club head ofFIG. 37;

FIG. 43 depicts a front perspective view of the golf club head of FIG.37;

FIG. 44 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 45 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 44;

FIG. 46 depicts a cross-sectional view of the golf club head of FIG. 44along the cross-sectional line XLVI-XLVI of FIG. 44;

FIG. 47 depicts a portion of the golf club head of FIG. 46;

FIG. 48 depicts a simplified cross-sectional view of the golf club headof FIG. 44, similar to the detailed cross-sectional view of the golfclub head in FIG. 47

FIG. 49 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 50 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 49;

FIG. 51 depicts a cross-sectional view of the golf club head of FIG. 49along the cross-sectional line LI-LI of FIG. 49;

FIG. 52 depicts a portion of the golf club head of FIG. 49;

FIG. 53 depicts a simplified cross-sectional view of the golf club headof FIG. 49, similar to the detailed cross-sectional view of the golfclub head in FIG. 51.

FIG. 54 depicts an interior view of a portion of the golf club head ofFIG. 49;

FIG. 55 depicts a front perspective view of the golf club head of FIG.49.

FIG. 56 depicts a back perspective view of a golf club head according tostill yet another embodiment;

FIG. 57 depicts a back, heel-side perspective view of the golf club headaccording to the embodiment of FIG. 56;

FIG. 58 depicts a cross-sectional view of the golf club head of FIG. 56along the cross-sectional line LVIII-LVIII of FIG. 56;

FIG. 59 depicts a portion of the golf club head of FIG. 58;

FIG. 60 depicts a simplified cross-sectional view of the golf club headof FIG. 56, similar to the detailed cross-sectional view of the golfclub head in FIG. 59;

FIG. 61 depicts a cross-sectional view of the heel portion of the golfclub head of FIG. 56, along the cross-sectional line LXI-LXI; and

FIG. 62 depicts an front view of the golf club head of FIG. 56, alongthe cross-sectional line LXII-LXII.

For simplicity and clarity of illustration, the drawing figuresillustrate the general manner of construction, and descriptions anddetails of well-known features and techniques may be omitted to avoidunnecessarily obscuring the golf clubs and their methods of manufacture.Additionally, elements in the drawing figures are not necessarily drawnto scale. For example, the dimensions of some of the elements in thefigures may be exaggerated relative to other elements to help improveunderstanding of embodiments of the golf clubs and their methods ofmanufacture. The same reference numerals in different figures denote thesame elements.

The terms “first,” “second,” “third,” “fourth,” and the like in thedescription and in the claims, if any, are used for distinguishingbetween similar elements and not necessarily for describing a particularsequential or chronological order. It is to be understood that the termsso used are interchangeable under appropriate circumstances such thatthe embodiments of golf clubs and methods of manufacture describedherein are, for example, capable of operation in sequences other thanthose illustrated or otherwise described herein. Furthermore, the terms“contain,” “include,” and “have,” and any variations thereof, areintended to cover a non-exclusive inclusion, such that a process,method, article, or apparatus that comprises a list of elements is notnecessarily limited to those elements, but may include other elementsnot expressly listed or inherent to such process, method, article, orapparatus.

The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “side,”“under,” “over,” and the like in the description and in the claims, ifany, are used for descriptive purposes and not necessarily fordescribing permanent relative positions. It is to be understood that theterms so used are interchangeable under appropriate circumstances suchthat the embodiments of golf clubs and methods of manufacture describedherein are, for example, capable of operation in other orientations thanthose illustrated or otherwise described herein. The term “coupled,” asused herein, is defined as directly or indirectly connected in aphysical, mechanical, or other manner.

DESCRIPTION OF EXAMPLES OF EMBODIMENTS

Various embodiments of the golf club heads with tiered internal thinsections include a golf club head comprising a body. The body comprisesa strikeface, a heel region, a toe region opposite the heel region, asole, a crown, and an internal radius transition region from thestrikeface to at least one of the sole or the crown. In manyembodiments, the internal radius transition region is not visible froman exterior of the golf club head and comprises a first tier, a secondtier, and a tier transition region between the first tier and the secondtier.

Another embodiment of the golf club heads with tiered internal thinsections include a golf club comprising a golf club head and a shaftcoupled to the golf club head. The golf club head comprises astrikeface, a heel region, a toe region opposite the heel region, asole, a crown, and an internal radius transition region from thestrikeface to at least one of the sole or the crown. In manyembodiments, the internal radius transition region is not visible froman exterior of the golf club head and comprises a first tier, a secondtier, and a tier transition region between the first tier and the secondtier.

Other embodiments of the golf club heads with tiered internal thinsections include a method for manufacturing a golf club head. The methodcomprises providing a body. The body comprises a strikeface, a heelregion, a toe region opposite the heel region, a sole, and a crown. Themethod further comprises providing an internal radius transition regionfrom the strikeface to at least one of the sole or the crown. Theinternal radius transition region is not visible from an exterior of thegolf club head and comprises a first tier, a second tier, and a tiertransition region between the first tier and the second tier. In manyembodiments, the first tier has a first thickness, the second tier has asecond thickness, and the second thickness is smaller than the firstthickness.

Various embodiments include a golf club head comprising a hollow body.The hollow body comprises a strikeface, a heel region, a toe regionopposite the heel region, a sole, and a crown. In many embodiments, thecrown comprises an upper region comprising a top rail, and a lowerregion. In some embodiments, a cavity is located below the top rail, islocated above the lower region of the crown, and is defined at least inpart by the upper and lower regions of the crown. In many embodiments,the cavity comprises a top wall, a back wall, a bottom incline, a backcavity angle measured between the top and back walls of the cavity, andat least one channel.

Some embodiments include a golf club comprising a hollow-bodied golfclub and a shaft coupled to the hollow-bodied golf club head. Thehollow-bodied golf club head comprises a strikeface, a heel region, atoe region opposite the heel region, a sole, and a crown. In manyembodiments, the crown comprises an upper region comprising a top rail,and a lower region. In some embodiments, a cavity is located below thetop rail, is located above the lower region of the crown, and is definedat least in part by the upper and lower regions of the crown. In manyembodiments, the cavity comprises a top wall, a back wall, a bottomincline, a back cavity angle measured between the top and back walls ofthe cavity, and at least one channel.

Other embodiments include a method for manufacturing a golf club head.In many embodiments, the method comprises providing a body. The bodyhaving a strikeface, a heel region, a toe region opposite the heelregion, a sole, and a crown. The crown comprises an upper regioncomprising a top rail and a lower region. In some embodiments, a cavityis located below the top rail, above the lower region of the crown, andis defined at least in part by the upper and lower regions of the crown.In many embodiments, the cavity comprises a top wall, a back walladjacent to the top wall, a bottom incline adjacent to the back wall, aback cavity angle measured between the top and back walls of the cavity,and at least one channel.

Various embodiments include a golf club head comprising a hollow body.The hollow body comprises a strikeface, a heel region, a toe regionopposite the heel region, a sole, and a crown. In many embodiments, thecrown comprises an upper region comprising a top rail, and a lowerregion comprising a lower exterior wall. In some embodiments, a cavityis located below the top rail, is located above the lower region of thecrown, and is defined at least in part by the upper and lower regions ofthe crown. In many embodiments, the cavity comprises a top wall, a backwall, a first inflection point adjacent the top wall and the back wall,a bottom incline, a second inflection point adjacent to the back walland the bottom incline, a third inflection point adjacent to the bottomincline and the lower exterior wall, a lower angle measured from betweenthe bottom incline and the lower exterior wall, the lower angle is lessthan 180 degrees, a back cavity angle measured between the top and backwalls of the cavity, and at least one channel.

Some embodiments include a golf club comprising a hollow-bodied golfclub and a shaft coupled to the hollow-bodied golf club head. Thehollow-bodied golf club head comprises a strikeface, a heel region, atoe region opposite the heel region, a sole, and a crown. In manyembodiments, the crown comprises an upper region comprising a top rail,and a lower region comprising a lower exterior wall. In someembodiments, a cavity is located below the top rail, is located abovethe lower region of the crown, and is defined at least in part by theupper and lower regions of the crown. In many embodiments, the cavitycomprises a top wall, a back wall, a first inflection point adjacent thetop wall and the back wall, a bottom incline, a second inflection pointadjacent to the back wall and the bottom incline, a third inflectionpoint adjacent to the bottom incline and the lower exterior wall, alower angle measured from between the bottom incline and the lowerexterior wall, the lower angle is less than 180 degrees, a back cavityangle measured between the top and back walls of the cavity, and atleast one channel.

Other embodiments include a method for manufacturing a golf club head.In many embodiments, the method comprises providing a body. The bodyhaving a strikeface, a heel region, a toe region opposite the heelregion, a sole, and a crown. The crown comprises an upper regioncomprising a top rail and a lower region comprising a lower exteriorwall. In some embodiments, a cavity is located below the top rail, abovethe lower region of the crown, and is defined at least in part by theupper and lower regions of the crown. In many embodiments, the cavitycomprises a top wall, a back wall, a first inflection point adjacent thetop wall and the back wall, a bottom incline, a second inflection pointadjacent to the back wall and the bottom incline, a third inflectionpoint adjacent to the bottom incline and the lower exterior wall, alower angle measured from between the bottom incline and the lowerexterior wall, the lower angle is less than 180 degrees, a back cavityangle measured between the top and back walls of the cavity, and atleast one channel.

Other examples and embodiments are further disclosed herein. Suchexamples and embodiments may be found in the figures, in the claims,and/or in the present description.

I. Golf Club Head with Cascading Sole

Turning to the drawings, FIG. 1 illustrates an embodiment of a golf clubhead 100. Golf club head 100 can be a wood-type golf club head. Forexample, golf club head 100 can be a fairway wood-type golf club head ora driver-type golf club head or a hybrid-type golf club head or aniron-type golf club head. Golf club head 100 comprises a body 101. Body101 comprises a strikeface 112, a heel region 102, a toe region 104, asole 106, and a crown 108. In FIG. 1, body 101 also comprises a skirt110 extending between sole 106 and crown 108. In some embodiments, body101 does not comprise skirt 110 or any skirt. FIG. 18 depicts a frontperspective view of a golf club 1800 according to an embodiment. In someembodiments, golf club 1800 comprises golf club head 100 and a shaft190.

In some embodiments, body 101 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S,), an aluminum alloy, or a composite material. In some embodiments,strikeface 112 can comprise stainless steel, titanium, aluminum, a steelalloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel,maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), analuminum alloy, or a composite material. In some embodiments, body 101can comprise the same material as strikeface 112. In some embodiments,body 101 can comprise a different material than strikeface 112.

FIG. 2 illustrates a cross-section of golf club head 100 along thecross-sectional line II-II in FIG. 1, according to one embodiment. FIG.2 shows an internal radius transition 210 from strikeface 112 to sole106, according to an embodiment. Internal radius transition 210 cancomprise a smooth transition, or internal radius transition 210 cancomprise a cascading sole of at least two tiers or levels of thickness.For example, internal radius transition 210 can comprise a cascadingsole having 2, 3, 4, 5, 6, or 7 tiers. In some embodiments, internalradius transition can provide more bending of strikeface 112. In someexamples, the increase in bending or deflection of strikeface 112 canallow approximately 1% to approximately 3% more energy from thedeflection of strikeface 112.

In many embodiments, internal radius transition 210 is not visible froman exterior of golf club head 100. FIG. 2 also shows a top internalradius transition 260 from strikeface 112 to crown 108. In someembodiments, top internal radius transition 260 can comprise a smoothtransition, while in other embodiments, top internal radius transition260 can comprise at least two tiers or levels of thickness. For example,top internal radius transition 260 can comprise 2, 3, 4, 5, 6, or 7tiers or levels of thickness. In some embodiments, golf club head 100also can have an internal sole thickness 220. Internal sole thickness220 can be thicker than the smallest thickness of internal radiustransition 210. In many embodiments, internal sole thickness 220 also isthicker than an adjacent tier or a final tier in internal radiustransition 210. In some embodiments, internal sole thickness 220 can bethicker than all of internal radius transition 210.

In some embodiments, internal radius transition 210 can be similar tothe sole front section and/or the weight distribution channels asdescribed in U.S. Pat. No. 8,579,728, entitled Golf Club Heads withWeight Redistribution Channels and Related Methods, which isincorporated by reference herein.

In some embodiments, the golf club head can comprise a cascadingtransition region, tiered transition region or internal radiustransition from the strikeface to at least one of a crown, a heel, atoe, a sole, or a skirt. In some embodiments, the golf club head cancomprise a single, continuous tiered transition region ring around acircumference of perimeter of the golf club head, for example a tieredtransition region ring from the strikeface to each of the crown, the toeregion, the heel region, and the sole region. In other embodiments, thegolf club head comprises a tiered transition region only at the crownand/or at the sole. In some embodiments, the golf club head comprises atiered transition region only at the toe region and/or at the heelregion. In other examples, the tiered transition region is only locatedfrom the strikeface to the skirt. In other embodiments, the golf clubhead comprises separate or individual tiered transition regions from thestrikeface to the toe region of the crown, the heel region of the crown,the toe region of the sole, and/or the heel region of the sole.

FIG. 3 depicts a view of an internal radius transition 310 of a golfclub head 300 that is similar to the golf club head of FIG. 1, along across-sectional line similar to the cross-sectional line II-II in FIG.1, according to another embodiment. FIG. 4 depicts a view of an internalradius transition 410 of a golf club head 400 that is similar to thegolf club head of FIG. 1, along a cross-sectional line similar to thecross-sectional line II-II in FIG. 1, according to another embodiment.FIG. 5 depicts a view of an internal radius transition 510 of a golfclub head 500 that is similar to the golf club head of FIG. 1, along across-sectional line similar to the cross-sectional line II-II in FIG.1, according to another embodiment.

As shown in FIG. 3, internal radius transition 310 can be can be similarto internal radius transition 210 (FIG. 2) and golf club head 300 can besimilar to golf club head 100 (FIGS. 1 and 2). Internal radiustransition 310 comprises a first tier 315 having a first thickness, anda second tier 317 having a second thickness. In many embodiments, thethickness of each tier is substantially constant. For example, the firstthickness of first tier 315 can comprise a first substantially constantthickness, and the second thickness of second tier 317 can comprise asecond substantially constant thickness. In other embodiments, firsttier 315 can comprise a first slope, wherein the first thickness offirst tier 315 is thicker closer to strikeface 312 and thinner closer toa tier transition region 316. Tier transition region 316 can comprise atier slope that is steeper than the first slope of first tier 315. Tiertransition region 316 can be linearly sloped at an angle less than 90degrees to transition from first tier 315 to second tier 317. In otherembodiments, tier transition region 316 can comprise an approximately 90degree step, as shown in tier transition regions 516 and 518 of FIG. 5.Tier transition region 516 (FIG. 5) and 518 (FIG. 5) can be similar totier transition region 316 (FIG. 3), and tier transition regions 416(FIG. 4) and 418 (FIG. 4).

As shown in FIG. 4, in some embodiments, each tiered transition 316,416, 418, 516, 518 can include a first arcuate surface 420 and a secondarcuate surface 422. The first arcuate surface 420 has a first radius ofcurvature and the second arcuate surface 422 has a second radius ofcurvature. The first radius of curvature and the second radius ofcurvature of each tiered transition 316, 416, 418, 516, 518 can be thesame, or the first radius of curvature and the second radius ofcurvature of each tiered transition 316, 416, 418, 516, 518 can bedifferent. For example, the first radius of curvature of the firstarcuate surface 420 can be the same as the second radius of curvature ofthe first arcuate surface 420, the first radius of curvature of thefirst arcuate surface 420 can be less than the second radius ofcurvature of the first arcuate surface 420, or the first radius ofcurvature of the first arcuate surface 420 can be greater than thesecond radius of curvature of the first arcuate surface 420. For furtherexample, the first radius of curvature of the second arcuate surface 422can be the same as the second radius of curvature of the second arcuatesurface 422, the first radius of curvature of the second arcuate surface422 can be less than the second radius of curvature of the secondarcuate surface 422, or the first radius of curvature of the secondarcuate surface 422 can be greater than the second radius of curvatureof the second arcuate surface 422.

Further, each of the tiered transitions 316, 416, 418, 516, 518 can havethe same first radius of curvature or a different first radius ofcurvature, and each of the tiered transitions 316, 416, 418, 516, 518can have the same second radius of curvature or a different secondradius of curvature. For example, the first radius of curvature of thefirst arcuate surface 420 can be the same as the first radius ofcurvature of the second arcuate surface 422, the first radius ofcurvature of the first arcuate surface 420 can be less than the firstradius of curvature of the second arcuate surface 422, or the firstradius of curvature of the first arcuate surface 420 can be greater thanthe first radius of curvature of the second arcuate surface 422. Forfurther example, the second radius of curvature of the first arcuatesurface 420 can be the same as the second radius of curvature of thesecond arcuate surface 422, the second radius of curvature of the firstarcuate surface 420 can be less than the second radius of curvature ofthe second arcuate surface 422, or the second radius of curvature of thefirst arcuate surface 420 can be greater than the second radius ofcurvature of the second arcuate surface 422.

The internal radius transition features (e.g. internal tier transition310, FIG. 3) can change where a peak bending of a golf club head occurs.The tiered transition region can create a “plastic hinge” at the peakbending, promoting more localized deformation due to impact with thegolf ball. In many embodiments, the buckling process starts at thelocation of the peak bending and the golf club head is optimized to stayjust under the critical buckling threshold. The intentional plastichinge allows the club to flex more in the crown and sole direction.Intentional Plastic Hinge allows control over exactly where and how muchthe crown and sole will flex by using the tiered features.

Using the internal radius transition, the stress of the golf club headcan be distributed across a larger volume of material, thus lowering thelocalized peak stress. In many embodiments, the additional flex fromcrown to sole allows the face to bend further based on the same loading.This additional flex can generate more stress and bending in the face ofthe club to create more spring energy. An increase in spring energy canbe stored in the golf club head due to an impact with the golf ball. Inmany embodiments, the additional spring energy will help to increaseball speed. In some embodiments, the internal radius transition cancreate more overall bending in the golf club head, which also can leadto more ball speed. Higher ball speeds across the strikeface can resultin better distance control. In some embodiments, the golf club head withinternal radius transition features can store approximately 4% toapproximately 6% more energy, which can then be returned to the golfball.

Returning to FIG. 3, internal radius transition 310 can change where apeak bending 350 of the sole of golf club head 300 occurs. In addition,internal radius transition 310 can engage more of the body of club head300 in the bending process on impact from a golf ball. In someembodiments, first tier 315 and second tier 317 allow some of the stresscreated by an impact of strikeface 312 with the golf ball to build up oneach tier. This structure can prevent the stress from collectingprimarily at the thinnest section of the sole to increase thereliability and durability of golf club head 300. In many embodiments,this structure creates a plastic hinge opposite the strikeface end ofinternal radius transition 310 and promotes more localized deformationat the plastic hinge location. In many embodiments, the plastic hingecan be located at the peak bending, for example, peak bending 350. Thisstructure also can allow for the storage of more potential energy, forexample, in the crown and/or the sole. In some embodiments, body 301 canexperience an increase of approximately 4% to approximately 7% in flexor bending in the crown to sole direction at the sole and/or the crown.The additional flex in the crown to sole direction at the sole and/orthe crown can allow strikeface 312 to bend further on the same loadingor impact by the golf ball. Therefore, this structure can create morestress and bending in strikeface 312 of golf club head 300 that can betransferred to the ball on impact with the strikeface 312.

In some embodiments, each tier comprises an approximately constantthickness throughout the tier. In many embodiments, first tier 315 isthicker than second tier 317. In some embodiments of a driver-type golfclub head, first tier 315 can be approximately 0.030 inch (0.076 cm) toapproximately 0.060 inch (0.152 cm) thick, or approximately 0.040 inch(0.102 cm) to approximately 0.050 inch (0.127 cm) thick, and second tier317 can be approximately 0.020 inch (0.051 cm) to approximately 0.050inch thick (0.127 cm), or approximately 0.030 inch (0.076 cm) toapproximately 0.040 inch (0.102 cm) thick. In some embodiments of afairway wood-type golf club head, first tier 315 can be approximately0.035 inch (0.089 cm) to approximately 0.065 inch (0.165 cm) thick, orapproximately 0.045 inch (0.114 cm) to approximately 0.055 inch (0.140cm) thick, and second tier 317 can be approximately 0.025 inch (0.064cm) to approximately 0.055 inch (0.140 cm) thick, or approximately 0.035inch (0.089 cm) to approximately 0.045 inch (0.114 cm) thick. In someembodiments of a hybrid-type golf club head, first tier 315 can beapproximately 0.050 inch (0.127 cm) to approximately 0.080 inch (0.203cm) thick, or approximately 0.060 inch (0.152 cm) to approximately 0.070inch thick (0.178 cm), and second tier 317 can be approximately 0.040inch (0.102 cm) to approximately 0.070 inch (0.178 cm) thick, orapproximately 0.050 inch (0.127 cm) to approximately 0.060 inch (0.152cm) thick. In many embodiments of an iron-type golf club head, the firsttier 315 can be approximately 0.055 inch (0.140 cm) to approximately0.085 inch (0.216 cm) thick, or approximately 0.060 inch (0.152 cm) toapproximately 0.080 inch thick (0.203 cm), and the second tier 317 canbe approximately 0.045 inch (0.114 cm) to approximately 0.075 inch(0.191 cm) thick, or approximately 0.050 inch (0.127 cm) toapproximately 0.070 inch (0.178 cm) thick.

In other embodiments, such as shown in FIG. 4, internal radiustransition 410 can have more than 2 tiers. For example, internal radiustransition 410 can have 2, 3, 4, 5, 6, or 7 tiers. A three tier internalradius transition 410 can be similar to internal radius transition 310(FIG. 3) and has a first tier 415, a second tier 417, and a third tier419. First tier 415 can be similar to first tier 315 in FIG. 3, andsecond tier 417 can be similar to second tier 317. In many embodiments,a peak bending 450 can occur further back from strikeface 412 as moretiers are added to the internal radius transition.

In many embodiments, second tier 417 is thicker than third tier 419. Insome embodiments of a driver-type golf club head, third tier 419 isapproximately 0.010 inch to approximately 0.040 inch (0.102 cm) thick,or approximately 0.020 inch (0.051 cm) to approximately 0.030 inch(0.076 cm) thick. In some embodiments of a fairway wood-type golf clubhead, third tier 419 is approximately 0.015 inch (0.038 cm) toapproximately 0.045 inch (0.114 cm) thick, or approximately 0.025 inch(0.064 cm) to approximately 0.035 inch (0.089 cm) thick. In someembodiments of a hybrid-type golf club head, third tier 419 isapproximately 0.030 inch (0.076 cm) to approximately 0.060 inch (0.152cm) thick, or approximately 0.040 inch (0.102 cm) to approximately 0.050inch (0.127 cm) thick. In some embodiments of an iron-type club head thethird tier 419 is approximately 0.030 inch (0.076 cm) to approximately0.060 inch (0.152 cm) thick, or approximately 0.035 inch (0.089 cm) toapproximately 0.055 inch (0.140 cm) thick.

Meanwhile, referring to FIG. 5, in some embodiments of a driver-typegolf club head, first tier 515 can be approximately 0.045 inch (0.114cm) thick; second tier 517 can be approximately 0.035 inch (0.089 cm)thick; and third tier 519 can be approximately 0.025 inch (0.064 cm)thick. In some embodiments of a fairway wood-type golf club head, firsttier 515 can be approximately 0.051 inch (0.130 cm) thick; second tier517 can be approximately 0.039 inch (0.099 cm) thick; and third tier 519can be approximately 0.030 inch (0.076 cm) thick. In some embodiments ofa hybrid-type golf club head, first tier 515 can be approximately 0.067inch (0.170 cm) thick; second tier 517 can be approximately 0.054 inch(0.137 cm) thick; and third tier 519 can be approximately 0.045 inch(0.114 cm) thick. In some embodiments of an iron-type club head, thefirst tier 515 can be approximately 0.067 inch (0.170 cm) thick; thesecond tier can be approximately 0.057 inch (0.145 cm) thick; and thethird tier 519 can be approximately 0.042 inch (0.107 cm) thick.

In some embodiments, first tiers 315, 415, 515 in FIGS. 3, 4, and 5,respectively, can have a first tier length that is approximately equalto a second tier length of second tiers 317, 417, 517 in FIGS. 3, 4, and5, respectively. In some embodiments, the first tier length of firsttiers 315, 415, 515 in FIGS. 3, 4, and 5, respectively, can have a firsttier length that is longer than the second tier length of second tiers317, 417, 517. In other embodiments, the second tier length of secondtiers 417, 517 in FIGS. 4 and 5, respectively, can be approximatelyequal to a third tier length of third tiers 419, 519 in FIGS. 4 and 5,respectively. In some embodiments, the second tier length of secondtiers 417, 517 in FIGS. 4 and 5, respectively, can be longer than thethird tier length of third tiers 419, 519 in FIGS. 4 and 5,respectively. In other embodiments, the second tier length of secondtiers 417, 517 in FIGS. 4 and 5, respectively, can be shorter than thethird tier length of third tiers 419, 519 in FIGS. 4 and 5,respectively.

Referring to FIGS. 3, 4, and 5, in some embodiments of a fairwaywood-type golf club head or a driver-type golf club head or ahybrid-type golf club head, the first tiers 315, 415, 515 can have firsttier lengths of approximately 0.05 inch (0.127 cm) to approximately 0.80inch (2.03 cm); the second tiers 317, 417, 517 can have second tierlengths of approximately 0.03 inch (0.076 cm) to approximately 0.60 inch(1.52 cm); and the third tiers 419, 519 can have third tier lengths ofapproximately 0.04 inch (0.102 cm) to approximately 0.70 inch (1.78 cm).In some embodiments of an iron-type golf club head, the first tiers 315,415, 515 can have first tier lengths of approximately 0.03 inch (0.076cm) to approximately 0.30 inch (0.762 cm); the second tiers 317, 417,517 can have second tier lengths of approximately 0.04 inch (0.102 cm)to approximately 0.40 inch (1.02 cm); and the third tiers 419, 519 canhave third tier lengths of approximately 0.05 inch (0.127 cm) toapproximately 0.50 inch (1.27 cm).

As shown in FIGS. 3, 4, and 5, in some embodiments, the first and thesecond arcuate surface of tiered transitions 316, 416, 516 can havefirst and second radii of curvatures that are at least two times largerthan the difference between the first thickness T1 and the secondthickness T2 of the first tier 315, 415, 515, and the second tier 317,417, 517, respectively. In one embodiment, the first and the secondarcuate surface of tiered transitions 316, 416, 516 has a first and asecond radius of curvature that are approximately 6.5 times larger thanthe difference between the first thicknesses T1 and the second thicknessT2 of the first tier 315, 415, 515 and the second tier 317, 417, 517,respectively. As shown in FIGS. 4 and 5, in some embodiments, the firstand the second arcuate surface of tiered transitions 418, 518 can havefirst and second radii of curvatures that are at least two times largerthan the difference between the second thickness T2 and the thirdthickness T₃ of the second tier 417, 517 and the third tier 419, 519,respectively. In one embodiment, the first and the second arcuatesurface of tiered transitions 418, 518 has a first and a second radiusof curvature that are approximately 6.5 times larger than the differencebetween the second thicknesses T2 and the third thickness T₃ of thesecond tier 417, 517 and the third tier 419, 519, respectively.

Some embodiments, such as golf club head 300, as shown in FIG. 3,comprise weight pad 330 to lower the center of gravity of golf club head300. Weight pad 330 comprises a weight pad thickness 331 that is greaterthan the final tier thickness 321 of the adjacent tier. In this example,the adjacent tier is second tier 317. In many embodiments which compriseweight pad 330, internal sole thickness 320 can be approximately equalto final tier thickness 321. In some embodiments, internal solethickness 320 can be thicker than final tier thickness 321. In someembodiments, internal sole thickness 320 is thinner than final tierthickness 321.

Some embodiments, such as golf club head 400, as shown in FIG. 4,comprise a rib 440. Rib 440 can be located internal to body 401 andapproximately parallel to the strikeface. In many embodiments, rib 440can be a ridge or bar. In some embodiments, rib 440 can have a ribthickness 441 that is greater than a third tier thickness 421, thethickness of the adjacent tier, or the thickness of the final tier ofinternal radius transition 410. The purpose for rib 440 is to reinforcethe sole of golf club head 400 so that the peak bending of the soleoccurs at tier transition region 416 and/or tier transition region 418.

Turning to FIG. 6, in some embodiments, golf club head 600 can comprisea crown internal radius transition 660 at crown 608. Crown internalradius transition 660 can be similar to internal radius transition 310in FIG. 3, except crown internal radius transition 660 is located at thestrikeface to crown transition instead of the strikeface to soletransition. In many embodiments, first tier 615 can be similar to firsttiers 315, 415, and/or 515 in FIGS. 3, 4, and 5, respectively; secondtier 617 can be similar to second tiers 317, 417, and/or 517 in FIGS. 3,4, and 5, respectively; third tier 619 can be similar to third tiers 419and/or 519 in FIGS. 4 and 5, respectively; and tier transition regions616 and/or 618 can be similar to tier transition regions 316, 416, 516,418, and/or 518 in FIGS. 3, 4, and 5. Similarly, the crown internalradius transition 660 can have several internal radius transitions toform more than two tiers. For example, the crown internal radiustransition 660 can have 2, 3, 4, 5, 6, or 7 tiers.

In FIG. 7, a golf club head 700 can comprise a skirt internal radiustransition 780 as shown in FIG. 7. FIG. 7 depicts a cross-sectional viewof golf club 700 similar to golf club head 100 (FIG. 1) along a similarcross-sectional line as the cross-sectional line VII-VII in FIG. 1,according to another embodiment. Skirt internal radius transition 780can be similar to internal radius transition 210 (FIG. 2), and firsttier 715 can be similar to first tiers 315, 415, and/or 515 in FIGS. 3,4, and 5, respectively; second tier 717 can be similar to second tiers317, 417, and/or 517 in FIGS. 3, 4, and 5; third tier 719 can be similarto third tiers 419 and/or 519 in FIGS. 4 and 5, respectively; and tiertransition regions 716 and/or 718 can be similar to tier transitionregions 316, 416, 516, 418, and/or 518 in FIGS. 3, 4, and 5. Similarly,skirt internal radius transition 780 can have more than two tiers. Forexample, skirt internal radius transition 780 can have 2, 3, 4, 5, 6, or7 tiers. As shown in FIG. 7, golf club head 700 also can comprise askirt internal radius transition at the other side of strikeface 712. Inanother embodiment, golf club head 700 can comprise a skirt internalradius transition at a single side of strikeface 712.

FIG. 8 depicts a view of a portion of a golf club head 800 similar togolf club head 400 (FIG. 4), according to an embodiment, and a view ofthe same area of standard golf club head 850. Standard golf club head850 comprises a uniform sole thickness 855 from a strikeface 852 to asole 856, and an internal sole weight 870 that is thicker than a uniformsole thickness 855. Golf club head 800 comprises an internal radiustransition 810 similar to internal radius transition 410 (FIG. 4).Internal radius transition 810 can comprise a first tier 815, similar tofirst tier 415 (FIG. 4), a second tier 817, similar to second tier 417(FIG. 4), and a third tier 819, similar to third tier 419 (FIG. 4).Internal radius transition 810 also can comprise tier transition regions816 and 818, similar to tier transition regions 416 (FIG. 4) and 418(FIG. 4), and internal sole weight 820 that is similar to internal soleweight 870. In many embodiments, at least one of first tier 815, secondtier 817, or third tier 819 can be thinner than uniform sole thickness855. The thinness of the tiers can save weight that can then beredistributed in the club head.

There is a greater dispersion of higher stress over a greater area ofsole 806 with internal transition region 810 than sole 856 without thecascading sole. In many embodiments, a general curve of a sole similarto uniform sole thickness 855 can absorb greater particularconcentrations of impact force from a golf ball in particular regions,but will not disperse the force over a larger area. The cascadingstructure (or tiers of varying thickness along the internal radiumtransition), such as internal radius transition 810, however provides atechnique to “package” the impact force from the golf ball over a largerarea as the undulating or tier structure transfers higher stresses fromone internal radium region of particular thickness to the next. In manyembodiments, there is a bleeding, overflow, or pooling of the stressover internal radius transition 810 or the cascading thin sole. Thegreater dispersion of the greater stress force provides a greaterrecoiling force to the strikeface. The pooling of the stress overinternal radius transition 810 also can prevent all of the stress fromcollecting directly at the thinnest tier. In many embodiments, thetiered features can help distribute the stress along the sole to preventone large stress riser. Instead, there are multiple stress risers for amore even distribution of the stress. The stresses are extended alongthe cascading sole, allowing the sole to take on (or absorb) morestress. The stress, however, decreases at the thickest portion of thesole that without the cascading sole experiences the highest level ofstress, and provides less spring back force to the strikeface.

An embodiment of a golf club head (e.g. 100, 300, 400, 500, 600, or 700)having the cascading sole was tested compared to a similar control clubhead devoid of a cascading sole. The club head with the cascading soleshowed an increase in ball speed of approximately 0.5 1.5 miles per hour(mph) (0.8-2.4 kilometers per hour, kph), or approximately 0.5-0.9%,compared to the control club head. The increase in ball speed for centerimpacts was approximately 0.5-1.0 mph (0.8-1.6 kph), and the increase inball speed for off-center impacts was approximately 1-1.5 mph (1.6-2.4kph). The club head with the cascading sole further showed an increasein launch angle of approximately 0.1-0.3 degrees, a decrease in spin ofapproximately 275-315 revolutions per minute (rpm), and an increase incarry distance of approximately 3-6 yards (2.7-5.5 meters) compared tothe control club head.

In some embodiments, the crown of a driver-type, hybrid-type, orwood-type golf club head having the cascading sole (e.g. 100, 300, 400,500, 600, or 700) may further include a first crown thickness (notshown) and a second crown thickness (not shown). The first crownthickness may be positioned on the crown behind the strikeface or crowninternal radius transition. The second crown thickness may be positionedon the crown behind the first crown thickness toward the rear of theclub head. The first crown thickness is greater than the second crownthickness. Further, the first crown thickness may transition to thesecond crown thickness gradually according to any profile, or the firstcrown thickness may transition to the second crown thickness abruptly,such as with a step.

The first crown thickness may comprise any portion of the crown on afront end of the club head. For example, the first crown thickness maycomprise 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any otherportion of the crown on the front end of the club head. The second crownthickness may comprise any portion of the crown on the rear of the clubhead. For example, the second crown thickness may comprise 40%, 45%,50%, 55%, 60%, 65%, 70%, 75%, 80%, or any other portion of the rear ofthe club head.

The crown thickness may transition between the first crown thickness andthe second crown thickness at any position on the crown of the clubhead, defining a crown thickness transition. The crown thicknesstransition may be any shape. In the exemplary embodiment, the crownthickness transition defines a bell-shaped curve, similar to thebell-shaped curve in U.S. Pat. No. 7,892,111, which is incorporatedherein by reference. The first crown thickness is positioned on thecrown between the strikeface and the bell-shaped curve, and the secondcrown thickness is positioned on the crown between the bell-shaped curveand the rear of the club head.

In the exemplary embodiment, the first crown thickness is approximately0.022 inches (0.056 cm) and the second crown thickness is approximately0.019 inches (0.048 cm) when the golf club head is a fairway wood typegolf club head. Further, in the exemplary embodiment, the first crownthickness is approximately 0.024 inches (0.061 cm) and the second crownthickness is approximately 0.019 inches (0.048 inches) when the golfclub head is a hybrid type golf club head.

In other embodiments of a fairway wood or hybrid type golf club head,the first crown thickness may be less than approximately 0.029 (0.074),0.028 (0.071), 0.027 (0.069), 0.026 (0.066), 0.025 (0.064), 0.024(0.061), 0.023 (0.058), 0.022 (0.056), 0.021 (0.053), 0.020 (0.051),0.019 (0.048), 0.018 (0.046), or 0.017 (0.043) inches (cm), and thesecond crown thickness may be less than approximately 0.024 (0.061),0.023 (0.058), 0.022 (0.056), 0.021 (0.053), 0.020 (0.051), 0.019(0.048), 0.018 (0.046), 0.017 (0.043), 0.016 (0.041), 0.015 (0.038),0.014 (0.036), 0.013 (0.033), or 0.012 (0.031) inches (cm).

The crown internal radius transition dissipates and/or reduces stresseson the crown of the club head, thereby allowing the first and the secondcrown thickness to be reduced compared to previous designs. In theexemplary embodiment, the first crown thickness is reduced byapproximately 17.2-24.1%, and the second crown thickness is reduced byapproximately 20.8% compared to previous designs. Reducing the first andthe second crown thickness allows the center of gravity of the club headto be lowered (positioned closer to the sole) compared to previousdesigns. The lowered center of gravity of the club head improves theperformance characteristics of the club head by reducing gearing andspin on the ball.

Turning to FIG. 9, various embodiments of golf club heads with tieredinternal thin sections include a method 900 for manufacturing a golfclub head. Method 900 comprises providing a body (block 910). The bodycomprises a strikeface, a heel region, a toe region opposite the heelregion, a sole, and a crown. In some embodiments, the body furthercomprises a skirt extending from the crown to the sole. Method 900further comprises providing an internal radius transition region fromthe strikeface to at least one of the sole, the crown, or the skirt(block 920). Method 900 further comprises providing a first tier of theinternal radius transition region (block 930), providing a second tierof the internal transition region (block 940), and providing a tiertransition region between the first tier and the second tier of theinternal transition region (block 950). In some embodiments, each ofblocks 910, 920, 930, 940, and 950 can be performed simultaneously witheach other such as by casting the body of a club head. In otherembodiments, one or more of blocks 920, 930, 940, and/or 950 can beperformed after block 910 through a machining process, as an example.

II. Golf Club Head with Back Cavity

In one embodiment, the golf club head has a back cavity located in anupper crown area of the golf club. In many embodiments, the back cavitycan provide a box spring affect when striking a golf ball. The backcavity can be combined with varying thicknesses of the internal radiusof the sole of the club head (cascading sole) to provide a spring likeeffect.

Some embodiments are directed to a club head (hybrid or fairway wood oriron with hollow design) that features a hollowed construction club headthat provides a more “iron-like” look and feel. In some embodiments, thegolf club head can feature a flat strikeface and iron-like profile,which can provide improved workability and accuracy, similar to an iron.A back cavity located below a top rail and along the upper crown of theclub head has been designed for hybrids, fairway woods and irons with ahollow construction. The back cavity may be a full channel from the heelto the toe just below the top rail and along the upper crown or backportion of the club head. The top rail and the cavity may be any design.In some embodiments, the cavity is angled at approximately 90 degreesand provides a targeted hinge point in the crown region of the golf clubhead. This hinge or buckling region enables the top rail to absorb moreof the impact force over a wider volumetric area causing the cavity andthe top rail to act as a springboard by returning more recoiled forceback to the strikeface as it returns to its original orientation therebyimparting more force into the ball. This greater club face deflection bythe cavity design can lead to less spin, a higher loft angle of the golfball upon impact, and greater ball speed with the same club speed overstandard golf club heads.

In a standard hybrid club head, the top rail and upper crown regions donot have a cavity of this design. In comparison to the presentdisclosure, there is less club strikeface bending or deflection in sucha standard hybrid club head. Standard hybrids are unable to have asgreat a spring-back effect because less energy is transferred to the toprail of the club due to the lack of a cavity. The disclosed golf clubhead with back cavity allows more of the impact force of the golf ballto be absorbed and then returned to the strikeface. In many embodiments,the angle of the cavity can provide a buckling point, or plastic hinge,or targeted hinge, for the strikeface to deflect more over the standardgolf club.

The recoiling effect of the cavity on the strikeface provides: (1) ahigher golf ball speed relative to the same club head speed of a clubhead with an upper crown cavity (or back cavity) and one without, due inpart to the spring effect that is transferred from the hinged region tothe strikeface to the ball; (2) less spin of the golf ball after impactwith the club, due in part to the hinge point above the cavity countersmore force being absorbed by the club and instead transfers more forceto the ball thereby preventing the ball from spinning backward off thestrikeface; and/or (3) a higher loft angle to the golf ball upon impact,due to the hinge and strikeface acting as a diving board or catapult tothe ball. In some embodiments, the cavity may provide an increase inball speed of approximately 1.0-1.2%, and an increase in launch angle ofapproximately 0.4-0.7 degrees.

Turning back to the drawings, FIG. 10 illustrates a back toe-sideperspective view of an embodiment of golf club head 1000 and FIG. 11illustrates a back heel-side perspective view of golf club head 1000according to the embodiment of FIG. 10. Golf club head 1000 can be ahybrid-type golf club head. In other embodiments, golf club head 1000can be an iron-type golf club head or a fairway wood-type golf clubhead. In many embodiments, golf club head 1000 does not include a badgeor a custom tuning port.

Golf club head 1000 comprises a body 1001. In many embodiments, the bodyis hollow. In some embodiments, the body is at least partially hollow.Body 1001 comprises a strikeface 1012, a heel region 1002, a toe region1004 opposite heel region 1002, a sole 1006, and a crown 1008. Crown1008 comprises an upper region 1011 and a lower region 1013. Upperregion 1011 comprises a top rail 1015. The top rail 1015 begins in thetoe region 1004, adjacent a top edge of the strikeface 1012, and extendsalong the top of the golf club head 1000 towards the heel region 1002.From a cross-sectional side view, such as in FIG. 12, the top rail 1015begins at the transition between the strikeface 1012 and a top of thegolf club head 1000 and ends at the transition between the top of thecrown 1008 of the golf club head 1000 and a section of the crown with adifferent orientation, such as a rear wall 1023. In some embodiments,top rail 1015 can be a flatter and taller top rail than in irons knownto one skilled in the art. The flatter and taller top rail cancompensate for mishits on strikeface 1012 to increase playability offthe tee.

In some embodiments, body 1001 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S), an aluminum alloy, or a composite material. In some embodiments,strikeface 1012 can comprise stainless steel, titanium, aluminum, asteel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4 stainless steel,maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4, T-9S), analuminum alloy, or a composite material. In some embodiments, body 1001can comprise the same material as strikeface 1012. In some embodiments,body 1001 can comprise a different material than strikeface 1012.

In many embodiments, a cavity 1030 is located below top rail 1015. Inmany embodiments, cavity 1030 comprises a top rail box spring design. Inmany embodiments, top rail 1015 and cavity 1030 provide an increase inthe overall bending of strikeface 1012. In some embodiments, the bendingof strikeface 1012 can allow for an approximately 2% to approximately 5%increase of energy. The cavity 1030 allows for the strikeface 1012 to bethinner and allow additional overall bending. For some fairway wood-typegolf club head embodiments, cavity 1030 can be a reverse scoop orindentation of crown 1008 with body 1001 comprising a greater thicknessor width toward sole 1006.

Referring to FIG. 10. in some embodiments, golf club head 1000 canfurther comprise an insert 1062 at lower region 1013 of crown 1008towards toe region 1004. Some embodiments comprise an internal weight atsole 1006. In many embodiments, insert 1062 may be comprised of tungstenor some other high density material. In many embodiments, the insertshifts the center of gravity (CG) back from strikeface 1012 byapproximately 0.04 inch (1 mm) to 0.10 inch (2.5 mm) and provides a 3.5%to 5.5% increase in launch angle, which can lead to an increase ofplayability off the tee and high or low mishits.

In many embodiments, the CG is in lower region 1013 of crown 1008, closeto the intersection of toe region 1004 and sole 1006. In someembodiments, the CG of golf club head 1000 is 0.597 inches along the CGyplane and 0.541 inches along the CGz plane. For the moment of inertia,Ixx, there was a 20.5% increase over the G30 iron and a 28% increaseover the Rapture DI by golf club head 1000. For Iyy, there was a 1.7%increase over the G30 iron and a 22% increase over Rapture DI.

In some embodiments, approximately 3 grams (g) to approximately 4 g isadded to top rail 1015. In most embodiments, the overall mass of golfclub head 1000 remains the same. In some embodiments, mass can beremoved from sole 1006 or toe region 1004 to offset the addition of massto top rail 1015. In some embodiments, adding the approximately 3 g toapproximately 4 g of mass to top rail 1015 can assist in the golf clubhead resisting turning. In some embodiments, the CG of the golf clubhead is slightly raised.

FIG. 12 illustrates a cross-section of golf club head 1000 along thecross-sectional line XII-XII in FIG. 10, according to one embodiment. Asseen in FIG. 12, strikeface 1012 comprises a high region 1076, a middleregion 1074, and a low region 1072. In many embodiments, upper region1011 of crown 1008 comprises the rear wall 1023, a top wall 1017 ofcavity 1030 below and adjacent to rear wall 1023, and a back wall 1019of cavity 1030 below and adjacent to top wall 1017.

In some embodiments, a height 1280 of rear wall 1023 of the upper region1011 of crown 1008 can be approximately 0.125 inch (0.318 cm) toapproximately 0.75 inch (1.91 cm), or approximately 0.150 inch (0.381cm) to approximately 0.400 inch (1.02 cm). For example, in someembodiments, the height 1280 of rear wall 1023 of the upper region 1011of crown 1008 can be approximately 0.175 inch (0.445 cm), 0.275 inch(0.699 cm), 0.375 inch (0.953 cm), 0.475 inch (1.21 cm), 0.575 inch(1.46 cm), or 0.675 inch (1.71 cm). In some embodiments, the height 1280of rear wall 1023 of the upper region 1011 of crown 1008 can beapproximately 5% to approximately 25% of the height of golf club head1000. In some embodiments, the length of top rail 1015, measured fromheel region 1002 to toe region 1004, can be approximately 70% toapproximately 95% of the length of golf club head 1000.

The height 1280 of rear wall 1023 of the upper region 1011 of crown1008, as described herein, allows cavity 1030 to absorb at least aportion of the stress on strikeface 1012 during impact with a golf ball.A golf club head having a rear wall height greater than the rear wallheight 1280 described herein would absorb less stress (and allow lessstrikeface deflection) on impact than the golf club head 1000 describedherein, due to increased dispersion of the impact stress along the toprail prior to reaching the cavity.

In some embodiments, cavity 1030 is located above lower region 1013 ofcrown 1008 and is defined at least in part by upper region 1011 andlower region 1013 of crown 1008. Cavity 1030 comprises a top wall 1017,a back wall 1019, and a bottom incline 1021. A first inflection point1082 is located between top wall 1017 of cavity 1030 and rear wall 1019of cavity. A second inflection point 1086 is located between rear wall1019 of cavity 1030 and bottom incline 1021.

The top wall 1017 and the rear wall 1019 of the external cavity 1030hinge about the first inflection point 1082. This hinge-like mobility atthe first inflection point 1082 allows greater strikeface 1012deflection &&&

In some embodiments, the height of back wall 1019, measured from firstinflection point 1082 to second inflection point 1086, can beapproximately 0.010 inch (0.25 mm) to approximately 0.138 inch (3.5 mm),or approximately 0.010 inch (0.25 mm) to approximately 0.059 inch (1.5mm). For example, the height of back wall 1019 can be approximately 0.01inch (0.25 mm), 0.02 inch (0.5 mm), 0.03 inch (0.75 mm), 0.04 inch (1.0mm), 0.05 inch (1.25 mm), 0.06 inch (1.5 mm), 0.07 inch (1.75 mm), 0.08inch (2.0 mm), 0.09 inch (2.25 mm), 0.10 inch (2.5 mm), 0.11 inch (2.75mm), 0.012 inch (3.0 mm), 0.13 inch (3.25 mm), or 0.14 inch (3.5 mm). Inmany embodiments, an apex of top wall 1017 can be approximately 0.125inch (0.318 cm) to approximately 1.25 inches (3.18 cm) or approximately0.25 inch (0.635 cm) to approximately 1.25 inches (3.18 cm) below anapex of top rail 1015. For example, the apex of top wall 1017 can beapproximately 0.125 inch (0.318 cm), 0.25 inch (0.635 cm), 0.375 inch(0.953 cm), 0.5 inch (1.27 cm), 0.625 inch (1.59 cm), 0.75 inch (1.91cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm),or 1.25 inches (3.18 cm) below the apex of top rail 1015.

In many embodiments, back wall 1019 of cavity 1030 can be substantiallyparallel to strikeface 1012. In other embodiments, back wall 1019 is notsubstantially parallel to strikeface 1012. In many embodiments, top wall1017 of cavity is angled toward strikeface 1012 when moving toward thefirst inflection point 1082. This orientation of top wall 1017 creates abuckling point or hinge point or plastic hinge to direct the stress ofimpact toward cavity 1030 and allowing increased flexing of strikeface1012 during impact.

Lower region 1013 of crown 1008 comprises bottom incline 1021 of cavity1030. In many embodiments, the second inflection point 1086, adjacent tobottom incline 1021, can be at least approximately 0.25 inch (0.635 cm)to approximately 2.0 inches (5.08 cm), or approximately 0.5 inch (1.27cm) to approximately 1.5 inches (3.81 cm) below the apex of top rail1015. For example, the second inflection point 1086 can be at leastapproximately 0.25 inch (0.635 cm), 0.5 inch (1.27 cm), 0.75 inch (1.91cm), 1.0 inch (2.53 cm), 1.25 inches (3.18 cm), 1.5 inches (3.81 cm),1.75 inches (4.45 cm) or 2.0 inches (5.08 cm) below the apex of top rail1015. In some embodiments, the maximum height of the bottom incline,measured from the sole 1006 of the club head 1000 to the secondinflection point 1086, can be at least approximately 0.25 inch (0.635cm) to approximately 3 inches (7.62 cm), or approximately 0.50 inch(1.27 cm) to approximately 2 inches (5.08 cm) above a lowest point ofthe sole 1006. For example, the second inflection point 1086 can be atleast approximately 0.25 inch (0.635 cm), 0.375 inch (0.953 cm), 0.5inch (1.27 cm), 0.625 inch (1.59 cm), 0.75 inch (1.91 cm), 0.825 inch(2.10 cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18cm), 1.375 inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12cm), 1.75 inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08cm), 2.125 inches 5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03cm), 2.5 inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00cm), 2.875 inches (7.30 cm), or 3.0 inches (7.62 cm) above a lowestpoint of the sole.

Cavity 1030 further comprises at least one channel 1039 (FIG. 10). Inmany embodiments, channel 1039 extends from heel region 1002 to toeregion 1004. A channel width 1032 (FIG. 12) can be substantiallyconstant throughout channel 1039. In some embodiments, channel width1032 (FIG. 12) can be approximately 0.008 inch (0.2 mm) to approximately1 inch (25 mm), or approximately 0.008 inch (0.2 mm) to approximately0.31 inch (8 mm). For example, channel width 1032 can be approximately0.008 inch (0.2 mm), 0.016 inch (0.4 mm), 0.024 inch (0.6 mm), 0.031inch (0.8 mm), 0.039 inch (1.0 mm), 0.079 inch (2 mm), 0.12 inch (3 mm),0.16 inch (4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm),0.31 inch (8 mm), 0.39 inch (10 mm), 0.59 inch (15 mm), 0.79 inch (20mm), or 0.98 inch (25 mm). In other embodiments, a channel toe regionwidth of channel 1039 is smaller than a channel heel region width ofchannel. In other embodiments, the channel heel region width is smallerthan the channel toe region width. In other embodiments, a channelmiddle region width of channel 1039 can be smaller than at least one ofthe channel heel region width or the channel toe region width. In otherembodiments, the channel middle region width can be greater than atleast one of the channel heel region width or the channel toe regionwidth. In some embodiments, channel 1039 is symmetrical. In otherembodiments, channel 1039 is non-symmetrical. In other embodiments,channel 1039 can further comprise at least two partial channels. In someembodiments, channel 1039 can comprise a series of partial channelsinterrupted by one or more bridges. In some embodiments, the one or morebridges can be approximately the same thickness as the thickness ofupper region 1011 of crown 1008.

The channel width 1032, as described herein, allows absorption of stressfrom strikeface 1012 on impact. A golf club head having a channel widthless than the channel width described herein (e.g. a golf club head witha less pronounced cavity) would allow less stress absorption from thestrikeface on impact (due to less material on the upper region 1011 ofcrown 1008), and therefore would experience less strikeface deflectionthan the golf club head 1000 described herein.

In many embodiments, cavity 1030 further comprises a back cavity angle1035. Back cavity angle is measured between top wall 1017 and back wall1019 of cavity 1030. In many embodiments, back cavity angle 1035 can beapproximately 70 degrees to approximately 110 degrees. In someembodiments, back cavity angle 1035 can be approximately 80 degrees toapproximately 100 degrees. In some embodiments, back cavity angle 1035is approximately 70, 75, 80, 85, 90, 95, 100, or 110 degrees. In manyembodiments, back cavity angle 1035 provides a buckling point or plastichinge or targeted hinge at a top rail hinge point 1070, upon golf clubhead 1000 impacting the golf ball. In some embodiments, the wallthickness at top rail hinge point 1070 is thinner than at top wall 1017of cavity 1030

FIG. 13 illustrates a view of crown 1008 of the cross-section of golfclub head 1000 of FIG. 12 alongside a similar cross-section of a golfclub head 1200 without a cavity along a similar cross-sectional lineXII-XII in FIG. 10. Golf club head 1200 comprises a strikeface 1212, acrown 1208, a top rail 1215, a top rail hinge point 1270, and a rearwall 1223. In many embodiments, golf club head 1000 comprises a rearangle 1040, a top rail angle 1045, and a strikeface angle 1050. Upperregion angle 1040 is measured from top wall 1017 to rear wall 1023 ofupper region 1011. In many embodiments, rear angle 1040 can beapproximately 70 degrees to approximately 110 degrees. In someembodiments, rear angle 1040 is approximately 90 degrees. Top rail angle1045 is measured from rear wall 1023 of upper region 1011 to top rail1015. In many embodiments, top rail angle 1045 can be approximately 35degrees to approximately 120 degrees or 70 degrees to approximately 110degrees. In some embodiments, top rail angle 1045 can be approximately35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115,or 120 degrees. Strikeface angle 1050 is measured from strikeface 1012to top rail 1015. In many embodiments, strikeface angle 1050 can beapproximately 70 degrees to approximately 160 degrees or 70 degrees toapproximately 110 degrees. In some embodiments, strikeface angle 1050 isapproximately 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130,135, 140, 145, 150, 155, or 160 degrees.

Referring to FIG. 13, in some embodiments, a minimum gap 1090 betweenstrikeface 1012 and back wall 1019 is approximately 0.079 inch (2 mm) toapproximately 0.39 inch (10 mm). For example, the minimum gap 1090between strikeface 1012 and back wall 1019 can be approximately 0.079inch (2 mm), 0.16 inch (4 mm), 0.24 inch (6 mm), 0.31 inch (8 mm), or0.39 inch (10 mm). In some embodiments, the minimum gap 1090 between thestrikeface 1012 and back wall 1019 is less than approximately 0.55 inch(14 mm), less than approximately 0.47 inch (12 mm), less thanapproximately 0.39 inch (10 mm), less than approximately 0.31 inch (8mm), less than approximately 0.24 inch (6 mm), or less thanapproximately 0.16 inch (4 mm). Further, in some embodiments, a maximumgap between strikeface 1012 and rear wall 1023 of upper region 1011 ofgolf club head 1000 is greater than minimum gap 1090. Further still, insome embodiments, a maximum gap between strikeface 1012 and bottomincline 1021 in lower region 1013 of golf club head 1000 is greater thanminimum gap 1090 and maximum gap in upper region 1011.

FIG. 21 illustrates a cross-sectional view of golf club head 1000,similar to the cross-section of the golf club head 1000 illustrated inFIG. 12. Golf club head 1000 includes cavity 1030, upper region 1011,and lower region 1013. Upper region 1011 includes upper exterior rearwall 1023, cavity 1030 includes cavity exterior wall 1025, and lowerregion 1013 includes lower exterior wall 1027. In many embodiments, amaximum upper distance 1092 measured as the perpendicular distance fromthe strikeface 1012 to the rear wall 1023 of upper region 1011 can beapproximately 0.20-0.59 inch (5-15 mm). For example, maximum upperdistance 1092 can be approximately 0.20 inch (5 mm), 0.24 inch (6 mm),0.28 inch (7 mm), 0.31 inch (8 mm), 0.35 inch (9 mm), 0.39 inch (10 mm),0.43 inch (11 mm), 0.47 inch (12 mm), 0.51 inch (13 mm), 0.55 inch (14mm), or 0.59 inch (15 mm). Further, a minimum cavity distance 1094measured as the perpendicular distance from the strikeface 1012 to thecavity exterior wall 1025 can be approximately 0.16-0.47 inch (4-12 mm).For example, minimum cavity distance 1094 can be approximately 0.16 inch(4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch(8 mm), 0.35 inch (9 mm), 0.39 inch (10 mm), 0.43 inch (11 mm), or 0.47inch (12 mm). Further still, a maximum lower distance 1096 measured asthe perpendicular distance from the strikeface 1012 to the lowerexterior wall 1027 can be approximately 0.98-1.57 inch (25-40 mm). Forexample, maximum lower distance 1096 can be approximately 0.98 inch (25mm), 1.02 inch (26 mm), 1.06 inch (27 mm), 1.10 inch (28 mm), 1.14 inch(29 mm), 1.18 inch (30 mm), 1.22 inch (31 mm), 1.26 inch (32 mm), 1.30inch (33 mm), 1.34 inch (34 mm), 1.38 inch (35 mm), 1.42 inch (36 mm),1.46 inch (37 mm), 1.50 inch (38 mm), 1.54 inch (39 mm), 1.57 inch or(40 mm). In many embodiments, maximum lower distance 1096 is greaterthan maximum upper distance 1092, and maximum upper distance 1092 isgreater than minimum cavity distance 1094.

In many embodiments, cavity 1030 can provide an increase in golf ballspeed over golf club head 1200 or other standard golf club heads, canreduce the spin rate of standard hybrids club heads, and can increasethe launch angle over both the standard hybrid and iron club heads. Inmany embodiments, the shape of cavity 1035 determines the level ofspring and timing of the response of golf club head 1000. When the golfball impacts strikeface 1012 of club head 1000 with cavity 1030,strikeface 1012 springs back like a drum, and crown 1008 bends in acontrolled buckle manner. In many embodiments, top rail 1015 can absorbmore stress over greater volumetric space than a top rail in a golf clubhead without cavity 1030. The length, depth and width of cavity 1030 canvary. These parameters provide control regarding how much spring back ispresent in the overall design of club head 1000.

Upon impact with the golf ball, strikeface 1012 can bend inward at agreater distance than on a golf club without cavity 1030. In someembodiments, strikeface 1012 has an approximately 10% to approximately50% greater deflection than a strikeface on a golf club head withoutcavity 1030. In some embodiments, strikeface 1012 has an approximately5% to approximately 40% or approximately 10% to approximately 20%greater deflection than a strikeface on a golf club head without cavity1035. For example, strikeface 1012 can have an approximately 5%, 10%,15%, 20%, 25%, 30%, 35% or 40% greater deflection than a strikeface on agolf club head without cavity 1035. In many embodiments, there is both agreater distance of retraction by strikeface 1012 due to the hinge andbending of cavity 1030 over a standard strikeface that does not have aback portion of the club without the cavity.

In many embodiments, the face deflection is greater with club head 1000having cavity 1030, as a greater buckling occurs along top rail hingepoint 1070 upon impact with the golf ball. Cavity 1030, however,provides a greater dispersion of stress along top rail hinge point 1070region of the top rail and the spring back force is transferred fromcavity 1030 and top rail 1015 to strikeface 1012. A standard top railwithout a cavity does not have this hinge/buckling effect, nor does itabsorb a high level of stress over a large volumetric area of the toprail. Therefore, the standard strikeface does not contract and thenrecoil as much as strikeface 1012. Further, both a larger region ofstrikeface 1012 and top rail 1015 absorb more stress than the same crownregion of a standard golf club head with a standard top rail and nocavity. In many embodiments, although there is greater stress along agreater area above cavity 1030 than the same area in a standard clubwithout the cavity, the durability of the club head with and without thecavity is the same. By adding more spring to the back end of the club(due to the inward inclination of top wall 1017 toward strikeface 1012),more force is displaced throughout the volume of the structure. Thestress is observed over a greater area of strikeface 1012 and top rail1015 of golf club head 1000. Peak stresses can be seen in the standardtop rail club head. However, more peak stresses are seen in golf clubhead 1000, but distributed over a large volume of the material. Thehinge and bend regions of golf club head 1000 (i.e., the region abovecavity 1030 and cavity 1030 itself) will not deform as long as thestress does not meet the critical buckling threshold. Cavity 1030 andits placement can be design to be under the critical K value of thebuckling threshold.

Turning ahead in the drawings, FIG. 22 illustrates a back perspectiveview of an embodiment of golf club head 2200 and FIG. 23 illustrates aback heel-side perspective view of golf club head 2200 according to theembodiment of FIG. 22. In some embodiments, golf club head 2200 can besimilar to golf club head 1000 (FIG. 10). Golf club head 2200 can be ahybrid-type golf club head. In other embodiments, golf club head 2200can be an iron-type golf club head or a fairway wood-type golf clubhead. In many embodiments, golf club head 2200 does not include a badgeor a custom tuning port.

Golf club head 2200 comprises a body 2201. In some embodiments, body2201 can be similar to body 1001 (FIG. 10). In many embodiments, thebody is hollow. In some embodiments, the body is at least partiallyhollow. Body 2201 comprises a strikeface 2212, a heel region 2202, a toeregion 2204 opposite heel region 2202, a sole 2206, and a rear 2210.Rear 2210 comprises an upper region 2211 and a lower region 2213. Upperregion 2211 comprises a top rail 2215. The top rail 2215 can be similarto the top rail 1015 of golf club head 1000. In some embodiments, toprail 2215 can be a flatter and taller top rail than in the in ironsknown to one skilled in the art. The flatter and taller top rail cancompensate for mis-hits on strikeface 2212 to increase playability offthe tee.

Body 2201 of FIGS. 22-26 further comprises a blade length. The bladelength for body 2201 can be measured similar to blade length 3725 asshown and described in FIG. 43 (i.e., a measurement parallel to the flatsurface of the strikeface 3712, from a toe edge 3726 of the strikeface3712, to strikeface end 3727 right before the strikeface 3712 integrallycurves into the hosel). The blade length of the body 2201 can range from2.80 inch (7.11 cm) to 3.00 inch (7.62 cm). For example, in someembodiments, the body 2201 can comprise a blade length of 2.80 inch(7.11 cm), 2.82 inch (7.16 cm), 2.84 inch (7.21 cm), 2.86 inch (7.26cm), 2.88 inch (7.32 cm), 2.90 inch (7.37 cm), 2.93 inch (7.44 cm), 2.94inch (7.47 cm), 2.96 inch (7.52 cm), 2.98 inch (7.57 cm), or 3.00 inch(7.62 cm).

The body 2201 further comprises a uniform thinned region transitioningfrom the bottom of the strikeface 2212 to the sole 2206, toward acascading sole portion of the sole (as described in greater detailbelow). In the illustrated embodiment, the uniform thinned regioncomprises a sole thickness measured perpendicular from the exteriorsurface 2225 to the interior surface at the uniform thinned region,which can remain constant from the bottom of the strikeface 2212 toadjacent the cascading sole portion of the sole. In some embodiments,the sole thickness of the uniform thinned region can be thinner than aconventional sole. For example, in some embodiments, the sole thicknessof the uniform thinned region may range from approximately 0.040 inch to0.080 inch. In other embodiments, the sole thickness of the uniformthinned region may be within the range of 0.040 inch to 0.050 inch,0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065inch to 0.080 inch. For example, the sole thickness of the uniformedthinned region can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060 inch,0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

In some embodiments, body 2201 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 2201can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 2212 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 2212 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 2201 can comprise the same material as strikeface2212. In some embodiments, body 2201 can comprise a different materialthan strikeface 2212.

In many embodiments, a cavity 2230 is located below top rail 2215. Insome embodiments, the length of top rail 2215, measured from heel region2202 to toe region 2204, can be approximately 70% to approximately 95%of the length of golf club head 2200. In many embodiments, cavity 2230comprises a top rail box spring design. In many embodiments, top rail2215 and cavity 2230 provide an increase in the overall bending ofstrikeface 2212. In some embodiments, the bending of strikeface 2212 canallow for an approximately 2% to approximately 5% increase of energy.The cavity 2230 allows for the strikeface 2212 to be thinner and allowadditional overall bending. For some fairway wood-type golf club headembodiments, cavity 2230 can be a reverse scoop or indentation of rear2210 with body 2201 comprising a greater thickness or width sole 2206.

FIG. 24 illustrates a cross-section of golf club head 2200 along thecross-sectional line XXIV-XXIV in FIG. 22, according to one embodiment.As seen in FIG. 24, strikeface 2212 comprises a high region 2476, amiddle region 2474, and a low region 2472. In many embodiments, upperregion 2211 of rear 2210 comprises a rear wall 2423, a top wall 2417 ofcavity 2230 below and adjacent to rear wall 2423, and a back wall 2219of cavity 2230 below and adjacent to top wall 2417. In some embodiments,a top wall length 2491 of top wall 2417 can be approximately 0.090 inch(0.229 cm) to approximately 0.130 inch (0.330 cm). In some embodiments,top wall length 2491 of top wall 2417 can be approximately 0.090 inch(0.229 cm), 0.100 inch (0.254 cm), 0.110 inch (0.279 cm), 0.120 inch(0.305 cm), or 0.130 inch (0.330 cm).

In some embodiments, a height 2480 of rear wall 2423 of the upper region2211 of rear 2210 can be approximately 0.125 inch (0.318 cm) toapproximately 0.75 inch (1.91 cm), or approximately 0.150 inch (0.381cm) to approximately 0.400 inch (1.02 cm). For example, in someembodiments, the height 2480 of rear wall 2423 of the upper region 2211of rear 2210 can be approximately 0.175 inch (0.445 cm), 0.275 inch(0.699 cm), 0.375 inch (0.953 cm), 0.475 inch (1.21 cm), 0.575 inch(1.46 cm), or 0.675 inch (1.71 cm). In some embodiments, the height 2480of rear wall 2423 of the upper region 2211 of rear 2210 can beapproximately 0.180 inch (0.4572 cm) to approximately 0.200 inch (0.508cm). In some embodiments, the height 2480 of rear wall 2423 of the upperregion 2211 of rear 2210 can be approximately 0.190 inch (0.4826 cm). Insome embodiments, the height 2480 of rear wall 2423 of the upper region2211 of rear 2210 can be approximately 5% to approximately 25% of theheight of golf club head 2200.

The height 2480 of rear wall 2423 of the upper region 2211 of rear 2210,as described herein, allows cavity 2230 to absorb at least a portion ofthe stress on strikeface 2212 during impact with a golf ball. A golfclub head having a rear wall height greater than rear wall height 2480described herein would absorb less stress (and allow less strikefacedeflection) on impact than the golf club head 2200 described herein, dueto increased dispersion of the impact stress along the top rail prior toreaching the cavity.

In some embodiments, cavity 2230 is located above a lower region 2213 ofrear 2210 and is defined at least in part by upper region 2211 and lowerregion 2213 of rear 2210. Cavity 2230 comprises the top wall 2417, theback wall 2219, and a bottom incline 2421. A first inflection point 2482is located between top wall 2417 of cavity 2230 and rear wall 2219 ofcavity. A second inflection point 2486 is located between rear wall 2219of cavity 2230 and bottom incline 2421.

In some embodiments, a height 2488 of back wall 2219, measured fromfirst inflection point 2482 to second inflection point 2486, can beapproximately 0.100 inch (0.254 cm) to approximately 0.600 inch (1.524cm). For example, height 2488 of back wall 2219 can be approximately0.100 inch (0.254 cm), 0.150 inch (0.381 cm), 0.200 inch (0.508 cm),0.250 inch (0.635 cm), 0.300 inch (0.762 cm), 0.350 inch (0.889 cm),0.400 inch (1.016 cm), 0.450 inch (1.143 cm), 0.500 inch (1.27 cm),0.550 inch (1.397 cm), or 0.600 inch (1.524 cm). In many embodiments,height 2488 of back wall 2219 can be approximately 0.420 inch (1.067 cm)to approximately 0.520 inch (1.321 cm). In some embodiments, height 2488of back wall 2219 can be approximately 0.420 inch (1.067 cm), 0.430 inch(01.092 cm), 0.440 inch (1.118 cm), 0.450 inch (1.143 cm), 0.460 inch(1.168 cm), 0.470 inch (1.194 cm), 0.480 inch (1.219 cm), 0.490 inch(1.245 cm), 0.500 inch (1.27 cm), 0.510 inch (1.295 cm), or 0.520 inch(1.321 cm).

In many embodiments, an apex of top wall 2417 can be approximately 0.125inch (0.318 cm) to approximately 1.25 inches (3.18 cm) or approximately0.25 inch (0.635 cm) to approximately 1.25 inches (3.18 cm) below anapex of top rail 2215. For example, the apex of top wall 2417 can beapproximately 0.125 inch (0.318 cm), 0.25 inch (0.635 cm), 0.375 inch(0.953 cm), 0.5 inch (1.27 cm), 0.625 inch (1.59 cm), 0.75 inch (1.91cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm),or 1.25 inches (3.18 cm) below the apex of top rail 2215.

In many embodiments, back wall 2219 of cavity 2230 can be substantiallyparallel to strikeface 2212. In other embodiments, back wall 2219 is notsubstantially parallel to strikeface 2212. In some embodiments, backwall 2219 of cavity 2230 is substantially parallel to rear wall 2423 ofupper region 2211 of rear 2210. In many embodiments, back wall 2219 ofcavity 2230 is angled away from strikeface 2212 when moving from firstinflection point 2482 to second inflection point 2486. This orientationof back wall 2219 creates a buckling point or hinge point or plastichinge to direct the stress of impact toward cavity 2230 and to allowincreased flexing of strikeface 2212 during impact.

Lower region 2213 of rear 2210 comprises the bottom incline 2421 ofcavity 2230 and a lower exterior wall 2427. In some embodiments, bottomincline 2421 of cavity 2230 can have a bottom incline length 2484measured from second inflection point 2486 to a third inflection point2492 positioned between bottom incline 2421 and lower exterior wall2427. In a number of embodiments, bottom incline length 2484 can beapproximately 0.150 inch (0.381 cm) to approximately 0.210 inch (0.533cm). In many embodiments, bottom incline length 2484 can beapproximately 0.150 inch (0.381 cm), 0.160 inch (0.406 cm), 0.170 inch(0.432 cm), 0.180 inch (0.457 cm), 0.190 inch (0.483 cm), 0.200 inch(0.508 cm), or 0.210 inch (0.533 cm).

In some embodiments, a lower angle 2451 can be measured from the betweenthe bottom incline 2421 and the lower exterior wall 2427. In someembodiments, lower angle 2451 can be less than 180 degrees. In a numberof embodiments, lower angle 2451 can be approximately 30 degrees to lessthan 180 degrees. In various embodiments, lower angle 2451 can beapproximately 70 degrees to approximately 130 degrees. In someembodiments, lower angle 2451 can be approximately 70, 75, 80, 85, 90,95, 100, 105, 110, 115, 120, 125, or 130 degrees.

In some embodiments, an inflection angle 2496 measured from back wall2219 to bottom incline 2421 can be approximately 70 degrees toapproximately 150 degrees. In some embodiments, inflection angle 2496can be approximately 90 degrees to approximately 130 degrees. In someembodiments, inflection angle 2496 is approximately 70, 75, 80, 85, 90,95, 100, 110, 115, 120, 125, 130, 135, 140, 145, or 150 degrees.

In many embodiments, second inflection point 2486, adjacent to bottomincline 2421, can be at least approximately 0.25 inch (0.635 cm) toapproximately 2.0 inches (5.08 cm), or approximately 0.5 inch (1.27 cm)to approximately 1.5 inches (3.81 cm) below the apex of top rail 2215.For example, the second inflection point 2486 can be at leastapproximately 0.25 inch (0.635 cm), 0.5 inch (1.27 cm), 0.75 inch (1.91cm), 1.0 inch (2.53 cm), 1.25 inches (3.18 cm), 1.5 inches (3.81 cm),1.75 inches (4.45 cm) or 2.0 inches (5.08 cm) below the apex of top rail2215. In some embodiments, the maximum height of the bottom incline,measured from the sole 2206 of the club head 2200 to second inflectionpoint 2486, can be at least approximately 0.25 inch (0.635 cm) toapproximately 3 inches (7.62 cm), or approximately 0.50 inch (1.27 cm)to approximately 2 inches (5.08 cm) above a lowest point of the sole2206. For example, the second inflection point 2486 can be at leastapproximately 0.25 inch (0.635 cm), 0.375 inch (0.953 cm), 0.5 inch(1.27 cm), 0.625 inch (1.59 cm), 0.75 inch (1.91 cm), 0.825 inch (2.10cm), 1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18 cm),1.375 inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12 cm),1.75 inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08 cm),2.125 inches 5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03 cm),2.5 inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00 cm),2.875 inches (7.30 cm), or 3.0 inches (7.62 cm) above a lowest point ofthe sole.

Cavity 2230 further comprises at least one channel 2239 (FIG. 22). Inmany embodiments, channel 2239 extends from heel region 2202 to toeregion 2204. A channel width 2432 (FIG. 24) measured from back wall 2219(FIG. 24) to rear wall 2423 (FIG. 24) and substantially perpendicular toa ground plane when golf club head 2200 is at address, can besubstantially constant throughout channel 2239. In some embodiments,channel width 2432 (FIG. 24) can be approximately 0.008 inch (0.2 mm) toapproximately 1 inch (25 mm), or approximately 0.008 inch (0.2 mm) toapproximately 0.31 inch (8 mm). For example, channel width 2432 can beapproximately 0.008 inch (0.2 mm), 0.016 inch (0.4 mm), 0.024 inch (0.6mm), 0.031 inch (0.8 mm), 0.039 inch (1.0 mm), 0.079 inch (2 mm), 0.12inch (3 mm), 0.16 inch (4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28inch (7 mm), 0.31 inch (8 mm), 0.39 inch (10 mm), 0.59 inch (15 mm),0.79 inch (20 mm), or 0.98 inch (25 mm). In other embodiments, a channeltoe region width of channel 2239 is smaller than a channel heel regionwidth of channel. In other embodiments, the channel heel region width issmaller than the channel toe region width. In other embodiments, achannel middle region width of channel 2239 can be smaller than at leastone of the channel heel region width or the channel toe region width. Inother embodiments, the channel middle region width can be greater thanat least one of the channel heel region width or the channel toe regionwidth. In some embodiments, channel 2239 is symmetrical from heel region2202 to toe region 2204. In other embodiments, channel 2239 isnon-symmetrical. In other embodiments, channel 2239 can further compriseat least two partial channels. In some embodiments, channel 2239 cancomprise a series of partial channels interrupted by one or morebridges. In some embodiments, the one or more bridges can beapproximately the same thickness as the thickness of upper region 2211of rear 2210.

The channel width 2432, as described herein, allows absorption of stressfrom strikeface 2212 on impact. A golf club head having a channel widthless than the channel width described herein (e.g. a golf club head witha less pronounced cavity) would allow less stress absorption from thestrikeface on impact (due to less material on the upper region 2211 ofrear 2210), and therefore would experience less strikeface deflectionthan the golf club head 2200 described herein.

In many embodiments, cavity 2230 further comprises a back cavity angle2435. Back cavity angle is measured between top wall 2417 and back wall2219 of cavity 2230. In many embodiments, back cavity angle 2435 can beapproximately 70 degrees to approximately 110 degrees. In someembodiments, back cavity angle 2435 can be approximately 80 degrees toapproximately 100 degrees. In some embodiments, back cavity angle 2435is approximately 70, 75, 80, 85, 90, 95, 100, or 110 degrees. In manyembodiments, back cavity angle 2435 provides a buckling point or plastichinge or targeted hinge at a top rail hinge point 2470, upon golf clubhead 2200 impacting the golf ball at strike face 2212. In someembodiments, the wall thickness at top rail hinge point 2470 is thinnerthan at top wall 2417 of cavity 2230

FIG. 25 illustrates a view of top rail 2215 and a portion of rear 2210of the cross-section of golf club head 2200 of FIG. 22 different fromcross-section of golf club head 1200 as shown in FIG. 13. In manyembodiments, golf club head 2200 comprises a rear angle 2540, a top railangle 2545, and a strikeface angle 2550. Rear angle 2540 is measuredfrom top wall 2417 to rear wall 2423 of upper region 2211. In manyembodiments, rear angle 2540 can be approximately 70 degrees toapproximately 110 degrees. In some embodiments, rear angle 2540 isapproximately 70, 75, 80, 85, 90, 95, 100, 105, or 110 degrees. Top railangle 2545 is measured from rear wall 2423 of upper region 2211 to toprail 2215. In many embodiments, top rail angle 2545 can be approximately35 degrees to approximately 120 degrees or 70 degrees to approximately110 degrees. In some embodiments, top rail angle 2545 can beapproximately 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100,105, 110, 115, or 120 degrees. Strikeface angle 2550 is measured fromstrikeface 2212 to top rail 2215. In many embodiments, strikeface angle2550 can be approximately 70 degrees to approximately 160 degrees or 70degrees to approximately 110 degrees. In some embodiments, strikefaceangle 2550 is approximately 70, 75, 80, 85, 90, 95, 100, 105, 110, 115,120, 125, 130, 135, 140, 145, 150, 155, or 160 degrees.

In some embodiments, a minimum gap 2590 measured perpendicularly to thestrikeface 2212 to the back wall 2219 is approximately 0.079 inch (2 mm)to approximately 0.39 inch (10 mm). For example, the minimum gap 2590between strikeface 2212 and back wall 2219 can be approximately 0.079inch (2 mm), 0.16 inch (4 mm), 0.24 inch (6 mm), 0.31 inch (8 mm), or0.39 inch (10 mm). In some embodiments, the minimum gap 2590 between thestrikeface 2212 and back wall 2219 is less than approximately 0.55 inch(14 mm), less than approximately 0.47 inch (12 mm), less thanapproximately 0.39 inch (10 mm), less than approximately 0.31 inch (8mm), less than approximately 0.24 inch (6 mm), or less thanapproximately 0.16 inch (4 mm). Further, in some embodiments, a maximumgap between strikeface 2212 and rear wall 2423 of upper region 2211 ofgolf club head 2200 is greater than minimum gap 2590. Further still, insome embodiments, a maximum gap between strikeface 2212 and bottomincline 2421 (FIG. 24) in lower region 2213 (FIG. 24) of golf club head2200 is greater than minimum gap 2590 and the maximum gap in upperregion 2211.

FIG. 26 illustrates a simplified cross-sectional view of golf club head2200, similar to the detailed cross-section of the golf club head 2200illustrated in FIG. 24. Golf club head 2200 includes the cavity 2230, anexterior surface 2225, the upper region 2211, and the lower region 2213.Upper region 2211 includes rear wall 2423, cavity 2230 includes cavityexterior wall 2225, top wall 2417, and back wall 221, while the lowerregion 2213 includes bottom incline 2421 and lower exterior wall 2427.In many embodiments, a maximum upper distance 2692 measured as theperpendicular distance from the exterior surface 2225 of the strikeface2212 to the exterior surface 2225 of the rear wall 2423 of upper region2211 can be approximately 0.20-0.59 inch (5-15 mm). For example, maximumupper distance 2692 can be approximately 0.20 inch (5 mm), 0.24 inch (6mm), 0.28 inch (7 mm), 0.31 inch (8 mm), 0.35 inch (8.89 mm), 0.39 inch(10 mm), 0.43 inch (11 mm), 0.47 inch (12 mm), 0.51 inch (13 mm), 0.55inch (14 mm), or 0.59 inch (15 mm). In some embodiments, maximum upperdistance 2692 can be approximately 0.355 inch (9.02 mm).

Further, a minimum upper distance 2694 measured as the perpendiculardistance from the exterior surface 2225 of the strikeface 2212 to theexterior surface 2225 of the back wall 2219 can be approximately0.16-0.47 inch (4-12 mm). For example, minimum upper distance 2694 canbe approximately 0.16 inch (4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm),0.28 inch (7 mm), 0.31 inch (8 mm), 0.35 inch (9 mm), 0.39 inch (10 mm),0.43 inch (11 mm), or 0.47 inch (12 mm). In some embodiments, minimumupper distance 2694 can be approximately 0.284 inch (7.21 mm).

Further still, a maximum lower distance 2696 measured as theperpendicular distance from the exterior surface 2225 of the strikeface2212 to the exterior surface 2225 of the lower exterior wall 2427 can beapproximately 0.98-1.57 inch (25-40 mm). For example, maximum lowerdistance 2696 can be approximately 0.98 inch (25 mm), 1.02 inch (26 mm),1.06 inch (27 mm), 1.10 inch (28 mm), 1.14 inch (29 mm), 1.18 inch (30mm), 1.22 inch (31 mm), 1.26 inch (32 mm), 1.30 inch (33 mm), 1.34 inch(34 mm), 1.38 inch (35 mm), 1.42 inch (36 mm), 1.46 inch (37 mm), 1.50inch (38 mm), 1.54 inch (39 mm), 1.57 inch or (40 mm). In someembodiments, maximum lower distance 2696 can be approximately 1.043 inch(26.5 mm). In many embodiments, maximum lower distance 2696 is greaterthan maximum upper distance 2692, and maximum upper distance 2692 isgreater than minimum upper distance 2694.

In many embodiments, cavity 2230 can provide an increase in golf ballspeed over golf club head 1200 (FIG. 25) or other standard golf clubheads, can reduce the spin rate of standard hybrids club heads, and canincrease the launch angle over both the standard hybrid and iron clubheads. In many embodiments, the shape of cavity 2230 determines thelevel of spring and timing of the response of golf club head 2200. Whenthe golf ball impacts strikeface 2212 of club head 2200 with cavity2230, strikeface 2212 springs back like a drum, and rear 2210 bends in acontrolled buckle manner. In many embodiments, top rail 2215 can absorbmore stress over greater volumetric space than a top rail in a golf clubhead without cavity 2230. The length, depth and width of cavity 2230 canvary. These parameters provide control regarding how much spring back ispresent in the overall design of club head 2200.

Upon impact with the golf ball, strikeface 2212 can bend inward at agreater distance than on a golf club without cavity 2230. In someembodiments, strikeface 2212 has an approximately 10% to approximately50% greater deflection than a strikeface on a golf club head withoutcavity 2230. In some embodiments, strikeface 2212 has an approximately5% to approximately 40% or approximately 10% to approximately 20%greater deflection than a strikeface on a golf club head without cavity2230. For example, strikeface 2212 can have an approximately 5%, 10%,15%, 20%, 25%, 30%, 35% or 40% greater deflection than a strikeface on agolf club head without cavity 2230. In many embodiments, there is both agreater distance of retraction by strikeface 2212 due to the hinge andbending of cavity 2230 over a standard strikeface that does not have aback portion of the club without the cavity.

In many embodiments, the face deflection is greater with club head 2200having cavity 2230, as a greater buckling occurs along top rail hingepoint 2470 upon impact with the golf ball. Cavity 2230, however,provides a greater dispersion of stress along top rail hinge point 2470region of the top rail, and the spring back force is transferred fromcavity 2230 and top rail 2215 to strikeface 2212. A standard top railwithout a cavity does not have this hinge/buckling effect, nor does itabsorb a high level of stress over a large volumetric area of the toprail. Therefore, the standard strikeface does not contract and thenrecoil as much as strikeface 2212. Further, both a larger region ofstrikeface 2212 and top rail 2215 absorb more stress than the same crownregion of a standard golf club head with a standard top rail and nocavity. In many embodiments, although there is greater stress along agreater area above cavity 2230 than the same area in a standard clubwithout the cavity, the durability of the club head with and without thecavity is the same. By adding more spring to the back end of the club(due to the inward inclination of top wall 2417 toward strikeface 2212),more force is displaced throughout the volume of the structure. Thestress is observed over a greater area of strikeface 2212 and top rail2215 of golf club head 2200. Peak stresses can be seen in the standardtop rail club head. However, more peak stresses are seen in golf clubhead 2200, but distributed over a large volume of the material. Thehinge and bend regions of golf club head 2200 (i.e., the region abovecavity 2230 and cavity 2230 itself) will not deform as long as thestress does not meet the critical buckling threshold. Cavity 2230 andits placement can be design to be under the critical K value of thebuckling threshold.

As shown in FIG. 26, a further deflection feature of the golf club head2200 can be the uniform thinned region 2660, located at the sole 2206and stretching between the rear 2210 of the body 2201 and the strikeface2212, toward a cascading sole portion of the sole (as described ingreater detail below). The uniform thinned region 2660 can providemultiple benefits. First, the uniform thinned region 2660 can reducestress on the strikeface 2212 caused during impact with the golf ball.Second, the uniform thinned region 2660 can bend allowing the strikeface2212 to experience greater deflection. Third, the uniform thinned region2660 removes weight from the sole area, allowing the weight to beredistributed more toward the rear of the golf club head 2200. Atimpact, the energy imparted to the strikeface 2212 by the golf ball cancause the uniform thinned region 2660 to bend outward, which in turnincreases the strikeface 2212 deflection. After bending, the uniformthinned region 2660 rebounds back to its original position returning themajority of the energy from impact back to the golf ball. The result isthe golf club head 2200 imparts increased ball speeds and greater traveldistances to the golf ball after impact.

Turning ahead in the drawings, FIG. 27 illustrates a back perspectiveview of an embodiment of golf club head 2700 and FIG. 28 illustrates aback heel-side perspective view of golf club head 2700 according to theembodiment of FIG. 27. In some embodiments, golf club head 2700 can besimilar to golf club head 1000 (FIG. 10), and/or golf club head 2200(FIG. 22). Golf club head 2700 can be a hybrid-type golf club head. Inother embodiments, golf club head 2700 can be an iron-type golf clubhead or a fairway wood-type golf club head. In many embodiments, golfclub head 2700 does not include a badge or a custom tuning port.

Golf club head 2700 comprises a body 2701. In some embodiments, body2701 can be similar to body 1001 (FIG. 10), and/or body 2201 (FIG. 22).In many embodiments, the body is hollow. In some embodiments, the bodyis at least partially hollow. Body 2701 comprises an exterior surface2703, a strikeface 2712, a heel region 2702, a toe region 2704 oppositeheel region 2702, a sole 2706, and a rear 2710.

Body 2701 of FIGS. 27-31 further comprises a blade length. The bladelength for body 2701 can be measured similar to blade length 3725 asshown and described in FIG. 43 (i.e., a measurement parallel to the flatsurface of the strikeface 3712, from a toe edge 3726 of the strikeface3712, to strikeface end 3727 right before the strikeface 3712 integrallycurves into the hosel). The blade length of the body 2701 can range from2.80 inch (7.11 cm) to 3.00 inch (7.62 cm). For example, in someembodiments, the body 2701 can comprise a blade length of 2.80 inch(7.11 cm), 2.82 inch (7.16 cm), 2.84 inch (7.21 cm), 2.86 inch (7.26cm), 2.88 inch (7.32 cm), 2.90 inch (7.37 cm), 2.93 inch (7.44 cm), 2.94inch (7.47 cm), 2.96 inch (7.52 cm), 2.98 inch (7.57 cm), or 3.00 inch(7.62 cm).

The body 2701 further comprises a uniform thinned region transitioningfrom the bottom of the strikeface 2712 to the sole 2706, toward acascading sole portion of the sole (as described in greater detailbelow). In the illustrated embodiment, the uniform thinned regioncomprises a sole thickness measured perpendicular from the exteriorsurface 2703 to the interior surface at the uniform thinned region,which can remain constant from the bottom of the strikeface 2712 toadjacent the cascading sole portion of the sole. In some embodiments,the sole thickness of the uniform thinned region can be thinner than aconventional sole. For example, in some embodiments, the sole thicknessof the uniform thinned region may range from approximately 0.040 inch to0.080 inch. In other embodiments, the sole thickness of the uniformthinned region may be within the range of 0.040 inch to 0.050 inch,0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065inch to 0.080 inch. For example, the sole thickness of the uniformedthinned region can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060 inch,0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 29 illustrates a cross-section of golf club head 2700 along thecross-sectional line XXIX-XXIX in FIG. 27, according to one embodiment.As seen in FIG. 29, strikeface 2712 comprises a high region 2976, amiddle region 2974, and a low region 2972. Rear 2710 comprises an upperregion 2711 and a lower region 2713 (FIG. 29). Upper region 2711comprises a top rail 2715, a rear wall 2923, and a top wall 2719. Thetop rail 2715 can be similar to the top rail 1015 of golf club head1000. In many embodiments, rear wall 2923 of rear 2710 is located belowand adjacent to top rail 2715, and a top wall 2719 of rear 2710 islocated below and adjacent to rear wall 2923. Lower region 2713comprises a back wall 2921, and a lower exterior wall 2927, wherein backwall 2921 is located below an adjacent the top wall 2719, and the lowerexterior wall 2927 is located below and adjacent the back wall 2921.Cavity 2730 is located on the exterior surface 2703, below the top rail2715 and rear wall 2923, above the lower region 2713 of rear 2710, andis defined by at least in part by upper region 2711 and lower region2713.

In some embodiments, top rail 2715 of the upper region 2711 of the rear2710 can be a flatter and taller top rail or skirt than in the in ironsknown to one skilled in the art. The flatter and taller top rail cancompensate for mis-hits on strikeface 2712 to increase playability offthe tee. In some embodiments, the length of top rail 2715, measured fromheel region 2702 to toe region 2704, can be 70% to 95% of the length ofgolf club head 2700. In many embodiments, cavity 2730 comprises a toprail box spring design. In many embodiments, top rail 2715 and cavity2730 provide an increase in the overall bending of strikeface 2712. Insome embodiments, the bending of strikeface 2712 can allow for a 2% to5% increase of energy. Cavity 2730 allows for strikeface 2712 to bethinner and allow additional overall bending. For some fairway wood-typegolf club head embodiments, cavity 2730 can be a reverse scoop orindentation of rear 2710 with body 2701 comprising a greater thicknessor width toward sole 2706.

In some embodiments, a height 2980 of rear wall 2923 of the upper region2711 of rear 2710 can range from 0.125 inch (0.318 cm) to 0.75 inch(1.91 cm), or 0.150 inch (0.381 cm) to 0.400 inch (1.02 cm). Forexample, in some embodiments, the height 2980 of rear wall 2923 of theupper region 2711 of rear 2710 can be 0.175 inch (0.445 cm), 0.275 inch(0.699 cm), 0.375 inch (0.953 cm), 0.475 inch (1.21 cm), 0.575 inch(1.46 cm), or 0.675 inch (1.71 cm). In some embodiments, the height 2980of rear wall 2923 of the upper region 2711 of rear 2710 can range from0.150 inch (0.381 cm) to 0.200 inch (0.508 cm). In some embodiments, theheight 2980 of rear wall 2923 of the upper region 2711 of rear 2710 canbe 0.170 inch (0.432 cm). In some embodiments, the height 2980 of rearwall 2923 of the upper region 2711 of rear 2710 can be 5% to 25% of theheight of golf club head 2700.

The height 2980 of rear wall 2923 of the upper region 2711 of rear 2710,as described herein, allows cavity 2730 to absorb at least a portion ofthe stress on strikeface 2712 during impact with a golf ball. A golfclub head having a rear wall height greater than rear wall height 2980described herein would absorb less stress (and allow less strikefacedeflection) on impact than golf club head 2700 described herein, due toincreased dispersion of the impact stress along the top rail prior toreaching the cavity.

In some embodiments, cavity 2730 is located above a lower region 2713 ofrear 2710 and is defined at least in part by upper region 2711 and lowerregion 2713 of rear 2710. Cavity 2730 comprises top wall 2719, and aback wall 2921. A first reference point 2922 is located between the toprail 2715 and rear wall 2923. A second reference point 2982 is locatedbetween rear wall 2923 and top wall 2719. A first inflection point 2986is located between top wall 2719 of cavity 2730 and back wall 2921. Athird reference point 2924 is a point located on top wall 2719 closestto the strikeface 2712. First reference point 2922 and second referencepoint 2982 create a first reference line 2929. Second reference point2982 and third reference point 2924 create a second reference line 2925.Third reference point 2924 and first inflection point 2986 create athird reference line 2926.

Golf club head 2700 further comprises a height 2988 of top wall 2719,measured parallel to strikeface 2712 and from the second reference point2982 to first inflection point 2986. In many embodiments, height 2988can range from 0.100 inch (0.254 cm) to 0.600 inch (1.524 cm). Forexample, height 2988 can be 0.100 inch (0.254 cm), 0.150 inch (0.381cm), 0.200 inch (0.508 cm), 0.250 inch (0.635 cm), 0.300 inch (0.762cm), 0.350 inch (0.889 cm), 0.400 inch (1.016 cm), 0.450 inch (1.143cm), 0.500 inch (1.27 cm), 0.550 inch (1.397 cm), or 0.600 inch (1.524cm). In many embodiments, height 2988 can range from 0.500 inch (1.27cm) to 0.600 inch (1.524 cm). In some embodiments, height 2488 of topwall 2719 can be 0.500 inch (1.27 cm), 0.510 inch (1.295 cm), 0.520 inch(1.321 cm), 0.530 inch (1.346 cm), 0.540 inch (1.372 cm), 0.550 inch(1.397 cm), 0.560 inch (1.422 cm), 0.570 inch (1.448 cm), 0.580 inch(1.473 cm), 0.590 inch (1.499 cm), or 0.600 inch (1.524 cm).

In many embodiments, second reference point 2982 can be 0.125 inch(0.318 cm) to 1.25 inches (3.18 cm) or 0.25 inch (0.635 cm) to 1.25inches (3.18 cm) to apex 2928 of top rail 2715. For example, the secondreference point 2982 can be 0.125 inch (0.318 cm), 0.25 inch (0.635 cm),0.375 inch (0.953 cm), 0.5 inch (1.27 cm), 0.625 inch (1.59 cm), 0.75inch (1.91 cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches(2.88 cm), or 1.25 inches (3.18 cm) below the apex 2928 of top rail2715.

In many embodiments, top wall 2719 of cavity 2730 can be substantiallyparallel to strikeface 2712. In other embodiments, top wall 2719 is notsubstantially parallel to strikeface 2712. In some embodiments, top wall2719 of cavity 2730 is substantially parallel to rear wall 2923 of upperregion 2711 of rear 2710. In a number of embodiments, a portion of topwall 2719 extends away from rear wall 2923 toward strikeface 2712 fromsecond reference point 2982 to third reference point 2924. In someembodiments, the portion of top wall 2719 extending away from rear wall2923 toward strikeface 2712 from second reference point 2982 to thirdreference point 2924 can be straight, curved upward, or curved downward.In many embodiments, a portion of top wall 2719 of cavity 2730 is angledaway from strikeface 2712 from third reference point 2924 to firstinflection point 2986. In some embodiments, the portion of top wall 2719angled away from strikeface 2712 from third reference point 2924 tofirst inflection point 2986 can be straight, curved upward, or curveddownward. This orientation of top wall 2719 creates a buckling point,hinge point or plastic hinge to direct the stress of impact towardcavity 2730 and to allow increased flexing of strikeface 2712 duringimpact.

Lower region 2713 of rear 2710 comprises back wall 2921 of cavity 2730and the lower exterior wall 2927. In some embodiments, back wall 2921 ofcavity 2730 can have a back wall length 2990 measured from firstinflection point 2986 to a second inflection point 2992 located betweenthe back wall 2921, and the lower exterior wall 2927. In a number ofembodiments, back wall length 2990 can range from 0.150 inch (0.381 cm)to 0.400 inch (1.02 cm). In many embodiments, back wall length 2990 canbe 0.150 inch (0.381 cm), 0.160 inch (0.406 cm), 0.170 inch (0.432 cm),0.180 inch (0.457 cm), 0.190 inch (0.483 cm), 0.200 inch (0.508 cm),0.210 inch (0.533 cm), 0.220 inch (0.559 cm), 0.230 inch (0.584 cm),0.240 inch (0.61 cm), 0.250 inch (0.635 cm), 0.260 inch (0.660 cm),0.270 inch (0.686 cm), 0.280 inch (0.711 cm), 0.290 inch (0.737 cm),0.300 inch (0.762 cm), 0.310 inch (0.787 cm), 0.320 inch (0.813 cm),0.330 inch (0.838 cm), 0.340 inch (0.864 cm), 0.350 inch (0.889 cm),0.360 inch (0.914 cm), 0.370 inch (0.94 cm), 0.380 inch (0.965 cm),0.390 inch (0.991 cm), or 0.400 inch (1.02 cm).

In some embodiments, a lower angle 2951 can be measured from between theback wall 2921 and the lower exterior wall 2927. In some embodiments,lower angle 2951 can be less than 180 degrees. In a number ofembodiments, lower angle 2951 can range from 30 degrees to 180 degrees.In various embodiments, lower angle 2951 can range from 70 degrees to130 degrees. In some embodiments, lower angle 2951 can be 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, or 130degrees.

In some embodiments, an inflection angle 2996 measured from thirdreference line 2926 to back wall 2921 can range from 70 degrees to 150degrees. In some embodiments, inflection angle 2996 can range from 90degrees to 130 degrees. In some embodiments, inflection angle 2996 canbe 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145degrees, or 150 degrees. In many embodiments, inflection angle 2996allows first inflection point 2986 to act as a buckling point or plastichinge upon golf club head 2700 impacting the golf ball at strike face2712. In some embodiments, the wall thickness at the first inflectionpoint 2986 can be thinner than at the top wall 2719 and back wall 2921.

In many embodiments, first inflection point 2986, adjacent to back wall2921, can range from 0.25 inch (0.635 cm) to 2.0 inches (5.08 cm), or0.5 inch (1.27 cm) to 1.5 inches (3.81 cm) below the apex 2928 of toprail 2715. For example, the first inflection point 2986 can be 0.25 inch(0.635 cm), 0.5 inch (1.27 cm), 0.75 inch (1.91 cm), 1.0 inch (2.53 cm),1.25 inches (3.18 cm), 1.5 inches (3.81 cm), 1.75 inches (4.45 cm) or2.0 inches (5.08 cm) below the apex 2928 of top rail 2715. In someembodiments, the maximum height of the back wall 2921, measuredperpendicular to a ground plane 2903 when golf club head 2700 is ataddress from a lowest point of sole 2706 to first inflection point 2986,can range from 0.25 inch (0.635 cm) to 3 inches (7.62 cm), or 0.50 inch(1.27 cm) to 2 inches (5.08 cm). For example, the first inflection point2986 can be 0.25 inch (0.635 cm), 0.375 inch (0.953 cm), 0.5 inch (1.27cm), 0.625 inch (1.59 cm), 0.75 inch (1.91 cm), 0.825 inch (2.10 cm),1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18 cm), 1.375inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12 cm), 1.75inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08 cm), 2.125inches (5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03 cm), 2.5inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00 cm), 2.875inches (7.30 cm), or 3.0 inches (7.62 cm) above a lowest point of sole2706 perpendicular to the ground plane 2903 when golf club head 2700 isat address.

In some embodiments, a back wall angle 2905 measured from back wall 2921to ground plane 2903 can range from 15 degrees to 45 degrees. In someembodiments, back wall angle 2905 can be 15 degrees, 16 degrees, 17degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29degrees 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

In some embodiments, cavity 2730 can further comprise at least onechannel 2739 (FIG. 27). In many embodiments, channel 2739 extends fromheel region 2702 (FIG. 27) to toe region 2704 (FIG. 27). Channel 2739comprises a channel width measured from second reference point 2982 totop wall 2719 substantially parallel to ground plane 2903, where channelwidth can vary in a direction from top rail 2715 to sole 2706. In someembodiments, a maximum channel width 2932, measured from firstinflection point 2986 to second reference point 2982 substantiallyparallel to ground plane 2903, can be substantially constant throughoutchannel 2739 from heel region 2702 to toe region 2704. In someembodiments, maximum channel width 2932 (FIG. 29) can range from 0.008inch (0.2 mm) to 1 inch (25 mm), or 0.008 inch (0.2 mm) to 0.31 inch (8mm). For example, maximum channel width 2932 can be 0.008 inch (0.2 mm),0.016 inch (0.4 mm), 0.024 inch (0.6 mm), 0.031 inch (0.8 mm), 0.039inch (1.0 mm), 0.079 inch (2 mm), 0.12 inch (3 mm), 0.16 inch (4 mm),0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch (8 mm),0.39 inch (10 mm), 0.59 inch (15 mm), 0.79 inch (20 mm), or 0.98 inch(25 mm). In other embodiments, a channel toe region width of channel2739 is less than a channel heel region width of channel 2739. In otherembodiments, the channel heel region width is less than the channel toeregion width. In other embodiments, a channel middle region width ofchannel 2739 can be less than at least one of the channel heel regionwidth or the channel toe region width. In other embodiments, the channelmiddle region width can be greater than at least one of the channel heelregion width or the channel toe region width. In some embodiments,channel 2739 is symmetrical from heel to toe. In other embodiments,channel 2739 is non-symmetrical. In other embodiments, channel 2739 canfurther comprise at least two partial channels. In some embodiments,channel 2739 can comprise a series of partial channels interrupted byone or more bridges. In some embodiments, the one or more bridges can beapproximately the same thickness as the thickness of top rail 2715.

Maximum channel width 2932, as described herein, allows absorption ofstress from strikeface 2712 on impact. A golf club head having a channelwidth less than the maximum channel width described herein (e.g. a golfclub head with a less pronounced cavity) would allow less stressabsorption from the strikeface on impact (due to less material on theupper region 2711 of rear 2710), and therefore would experience lessstrikeface deflection than golf club head 2700 described herein.

In many embodiments, cavity 2730 further comprises a back cavity angle2935. Back cavity angle 2935 is measured from first reference line 2929to second reference line 2925. In many embodiments, back cavity angle2935 can range from 15 degrees to 80 degrees. In some embodiments, backcavity angle 2935 is 15 degrees, 20 degrees, 25 degrees, 30 degrees, 35degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65degrees, 70 degrees, 75 degrees or 80 degrees.

FIG. 30 illustrates a view of top rail 2715 and a portion of rear 2710of the cross-section of golf club head 2700 of FIG. 27 different fromcross-section of golf club head 1200 as shown in FIG. 13. In manyembodiments, golf club head 2700 comprises a rear angle 3040, a top railangle 3045, and a strikeface angle 3050. Rear angle 3040 is measuredfrom second reference line 2925 to rear wall 2923 of upper region 2711.In many embodiments, rear angle 3040 can range from 70 degrees to 140degrees. In some embodiments, rear angle 3040 can be 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, or 140 degrees. Top rail angle 3045 is measuredfrom rear wall 2923 of upper region 2711 to top rail 2715. In manyembodiments, top rail angle 3045 can range from 35 degrees to 120degrees or 70 degrees to 110 degrees. In some embodiments, top railangle 3045 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees,115 degrees, or 120 degrees. Strikeface angle 3050 is measured fromstrikeface 2712 to top rail 2715. In many embodiments, strikeface angle3050 can range from 70 degrees to 160 degrees or 70 degrees to 110degrees. In some embodiments, strikeface angle 3050 can be 70 degrees,75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155degrees, or 160 degrees.

Upper region 2711 further comprises a minimum gap 3090 measured fromthird reference point 2924 of an inner surface 2919 of top wall 2719 toan inner surface 2919 of strikeface 2712, perpendicular to strikeface2712. In some embodiments, minimum gap 3090 can range from 0.079 inch (2mm) to 0.39 inch (10 mm). For example, the minimum gap 3090 can be 0.079inch (2 mm), 0.16 inch (4 mm), 0.24 inch (6 mm), 0.31 inch (8 mm), or0.39 inch (10 mm). In other embodiments, the minimum gap 3090 can rangefrom 0.16 inch (4 mm) to 0.55 inch (14 mm). In some embodiments, theminimum gap 3090 can be 0.55 inch (14 mm), 0.47 inch (12 mm), 0.39 inch(10 mm), 0.31 inch (8 mm), 0.24 inch (6 mm), or 0.16 inch (4 mm).

FIG. 31 illustrates a simplified cross-sectional view of golf club head2700, similar to the detailed cross-section of golf club head 2700illustrated in FIG. 29. Golf club head 2700 includes cavity 2730, upperregion 2711, lower region 2713, and exterior surface 2703. In manyembodiments, a maximum upper distance 3192 measured as the perpendiculardistance from exterior surface 2703 of strikeface 2712 to exteriorsurface 2703 of second reference point 2982 of upper region 2711 canrange from 0.20 inch to 0.59 inch (5 mm to 15 mm). For example, maximumupper distance 3192 can be 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch(7 mm), 0.31 inch (8 mm), 0.35 inch (8.89 mm), 0.39 inch (10 mm), 0.43inch (11 mm), 0.47 inch (12 mm), 0.51 inch (13 mm), 0.55 inch (14 mm),or 0.59 inch (15 mm). In some embodiments, maximum upper distance 3192can be 0.358 inch (9.09 mm). Further, a minimum upper distance 3194measured as the perpendicular distance from exterior surface 2703 ofstrikeface 2712 to exterior surface 2703 of third inflection point 2924can range from 0.09 inch to 0.47 inch (2.28 mm to 12 mm). For example,minimum upper distance 3194 can be 0.16 inch (4 mm), 0.20 inch (5 mm),0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch (8 mm), 0.35 inch (9 mm),0.39 inch (10 mm), 0.43 inch (11 mm), or 0.47 inch (12 mm). In someembodiments, minimum upper distance 3194 can be 0.309 inch (7.85 mm).Further still, a maximum lower distance 3196 measured as theperpendicular distance from exterior surface 2703 of strikeface 2712 toexterior surface 2703 of a fourth reference point 2920 located betweenthe lower exterior wall 2927 and the sole 2706 can range from 0.98 inchto 1.57 inch (25 mm to 40 mm). For example, maximum lower distance 3196can be 0.98 inch (25 mm), 1.02 inch (26 mm), 1.06 inch (27 mm), 1.10inch (28 mm), 1.14 inch (29 mm), 1.18 inch (30 mm), 1.22 inch (31 mm),1.26 inch (32 mm), 1.30 inch (33 mm), 1.34 inch (34 mm), 1.38 inch (35mm), 1.42 inch (36 mm), 1.46 inch (37 mm), 1.50 inch (38 mm), 1.54 inch(39 mm), 1.57 inch or (40 mm). In some embodiments, maximum lowerdistance 3196 can be 1.302 inch (33.1 mm). In many embodiments, maximumlower distance 3196 is greater than maximum upper distance 3192, andmaximum upper distance 3192 is greater than minimum upper distance 3194.

In many embodiments, cavity 2730 can provide an increase in golf ballspeed over golf club head 1200 (FIG. 30) or other standard golf clubheads, can reduce the spin rate of standard hybrids club heads, and canincrease the launch angle over both the standard hybrid and iron clubheads. In many embodiments, the shape of cavity 2730 determines thelevel of spring and timing of the response of golf club head 2700. Whenthe golf ball impacts strikeface 2712 of club head 2700 with cavity2730, strikeface 2712 springs back like a drum, and rear 2710 bends in acontrolled buckle manner. In many embodiments, top rail 2715 can absorbmore stress over greater volumetric space than a top rail in a golf clubhead without cavity 2730. The length, depth and width of cavity 2730 canvary. These parameters provide control regarding how much spring back ispresent in the overall design of club head 2700.

Upon impact with the golf ball, strikeface 2712 can bend inward at agreater distance than on a golf club without cavity 2730. In someembodiments, strikeface 2712 has a 10% to a 50% greater deflection thana strikeface on a golf club head without cavity 2730. In someembodiments, strikeface 2712 has a 5% to a 40% or a 10% to a 20% greaterdeflection than a strikeface on a golf club head without cavity 2730.For example, strikeface 2712 can have a 5%, 10%, 15%, 20%, 25%, 30%, 35%or 40% greater deflection than a strikeface on a golf club head withoutcavity 2730. In many embodiments, there is both a greater distance ofretraction by strikeface 2712 due to the hinge and bending of cavity2730 over a standard strikeface that does not have a back portion of theclub without the cavity.

In many embodiments, the face deflection is greater with club head 2700having cavity 2730, as a greater buckling occurs at first inflectionangle 2986 of top wall 2719 upon impact with a golf ball. Cavity 2730,however, provides a greater dispersion of stress along top rail 2715,rear wall 2923, and top wall 2719, and the spring back force istransferred from cavity 2730 and first inflection point 2986 of top wall2719 to strikeface 2712. A standard top rail, rear wall and top wallwithout a cavity does not have this hinge/buckling effect, nor does itabsorb a high level of stress over a large volumetric area of the toprail, rear wall and top wall. Therefore, the standard strikeface doesnot contract and then recoil as much as strikeface 2712. Further, both alarger region of strikeface 2712, top rail 2715, rear wall 2923, and topwall 2719 absorb more stress than the same crown region of a standardgolf club head with a standard top rail, top wall and no cavity. In manyembodiments, although there is greater stress along a greater area abovecavity 2730 than the same area in a standard club without the cavity,the durability of the club head with and without the cavity is the same.By adding more spring to the back end of the club (due to the inwardinclination of a portion of top wall 2719 toward strikeface 2712), moreforce is displaced throughout the volume of the structure. The stress isobserved over a greater area of strikeface 2712, top rail 2715, rearwall 2923, and top wall 2719 of golf club head 2700. Peak stresses canbe seen in the standard top rail club head. However, more peak stressesare seen in golf club head 2700, but distributed over a large volume ofthe material. The hinge and bend regions of golf club head 2700 (i.e.,the region above cavity 2730 and cavity 2730 itself) will not deform aslong as the stress does not meet the critical buckling threshold. Cavity2730 and its placement can be design to be under the critical K value ofthe buckling threshold.

As shown in FIG. 31, a further deflection feature of the golf club head2700 can be the uniform thinned region 3160, located at the sole 2706and stretching between the rear 2710 of the body 2701 and the strikeface2712, toward a cascading sole portion of the sole (as described ingreater detail below). The uniform thinned region 3160 can providemultiple benefits. First, the uniform thinned region 3160 can reducestress on the strikeface 2712 caused during impact with the golf ball.Second, the uniform thinned region 3160 can bend allowing the strikeface2712 to experience greater deflection. Third, the uniform thinned region3160 removes weight from the sole area, allowing the weight to beredistributed more toward the rear of the golf club head 2700. Atimpact, the energy imparted to the strikeface 2712 by the golf ball cancause the uniform thinned region 3160 to bend outward, which in turnincreases the strikeface 2712 deflection. After bending, the uniformthinned region 3160 rebounds back to its original position returning themajority of the energy from impact back to the golf ball. The result isthe golf club head 2700 imparts increased ball speeds and greater traveldistances to the golf ball after impact.

In some embodiments, body 2701 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 2701can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 2712 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 2712 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 2701 can comprise the same material as strikeface2712. In some embodiments, body 2701 can comprise a different materialthan strikeface 2712.

FIG. 32 illustrates a back perspective view of an embodiment of golfclub head 3200, and FIG. 33 illustrates a back heel-side perspectiveview of golf club head 3200 according to the embodiment of FIG. 32. Insome embodiments, golf club head 3200 can be similar to golf club head1000 (FIG. 10), golf club head 2200 (FIG. 22), and/or golf club head2700 (FIG. 27). Golf club head 3200 can be an iron-type golf club head.In other embodiments, golf club head 3200 can be a hybrid-type, or afairway wood-type golf club head. In some embodiments, golf club head3200 does not comprise a badge or a custom tuning port.

Golf club head 3200 comprises a body 3201. In some embodiments, body3201 can be similar to body 1001 (FIG. 10), body 2201 (FIG. 22), and/orbody 2701 (FIG. 27). In some embodiments, the body 3201 is hollow. Inother embodiments, the body is at least partially hollow. Body 3201comprises an exterior surface 3203, a strikeface 3212, a heel region3202, a toe region 3204 opposite the heel region 3202, a sole 3206, atop rail 3215, and a rear 3210.

Body 3201 of FIGS. 32-36 further comprises a blade length. The bladelength for body 3201 can be measured similar to blade length 3725 asshown and described in FIG. 43 (i.e., a measurement parallel to the flatsurface of the strikeface 3712, from a toe edge 3726 of the strikeface3712, to strikeface end 3727 right before the strikeface 3712 integrallycurves into the hosel). The blade length of the body 3201 can range from2.70 inch (6.86 cm) to 3.00 inch (7.62 cm). For example, in someembodiments, the body 3201 can comprise a blade length of 2.74 inch(6.96 cm), 2.78 inch (7.06 cm), 2.82 inch (7.16 cm), 2.86 inch (7.26cm), 2.90 inch (7.37 cm), 2.94 inch (7.47 cm), 2.98 inch (7.57 cm), or3.00 inch (7.62 cm).

The body 3201 further comprises a uniform thinned region transitioningfrom the bottom of the strikeface 3212 to the sole 3206, toward acascading sole portion of the sole (as described in greater detailbelow). In the illustrated embodiment, the uniform thinned regioncomprises a sole thickness measured perpendicular from the exteriorsurface 3203 to the interior surface at the uniform thinned region,which can remain constant from the bottom of the strikeface 3212 toadjacent the cascading sole portion of the sole. In some embodiments,the sole thickness of the uniform thinned region can be thinner than aconventional sole. For example, in some embodiments, the sole thicknessof the uniform thinned region may range from approximately 0.040 inch to0.080 inch. In other embodiments, the sole thickness of the uniformthinned region may be within the range of 0.040 inch to 0.050 inch,0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065inch to 0.080 inch. For example, the sole thickness of the uniformedthinned region can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060 inch,0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 34 illustrates a cross-section of golf club head 3200 along thecross-sectional line XXXIV-XXXIV in FIG. 32, according to oneembodiment. As seen in FIG. 32, strikeface 3212 comprises a high region3476, a middle region 3474, and a low region 3472. Rear 3210 cancomprises an upper region 3211, a lower region 3213, and a cavity 3230.Upper region 3211 comprises top rail 3215, a rear wall 3423, and a topwall 3219. In many embodiments, the rear wall 3423 of rear 3210 islocated below and adjacent to the top rail 3215, and the top wall 3219of rear 3210 is located below and adjacent to rear wall 3423. Lowerregion 3213 comprises a back wall 3421, and a lower exterior wall 3427.Cavity 3230 is located on the exterior surface 3203, below the top rail3215 and rear wall 3423, above the lower exterior wall 3427 of rear3210, and is defined by at least in part by upper region 3211 and lowerregion 3213.

In some embodiments, top rail 3215 of the upper region 3211 can be aflatter and taller top rail or skirt than in irons known to one skilledin the art. The flatter and taller rail 3215 can compensate for mis-hitson strikeface 3212 to increase playability off the tee. In someembodiments, the length of top rail 3215, measured from heel region 3202to toe region 3204, can be 70% to 95% of the length of golf club head3200. In many embodiments, cavity 3230 comprises a top rail box springdesign. In many embodiments, top rail 3215 and cavity 3230 provide anincrease in the overall bending of strikeface 3212. In some embodiments,the bending of strikeface 3212 can allow for a 2% to 5% increase ofenergy. Cavity 3230 allows for strikeface 3212 to be thinner and allowadditional overall bending. For some fairway iron-type golf club headembodiments, cavity 3230 can be a reverse scoop or indentation of rear3210 with body 3201 comprising a greater thickness toward sole 3206.

In some embodiments, a height 3480 of rear wall 3423 of upper region3211 of rear 3210 can range from 0.115 inch (0.292 cm) to 0.25 inch(0.635 cm), or 0.130 inch (0.330 cm) to 0.20 inch (0.508 cm). Forexample, in some embodiments, the height 3480 of rear wall 3423 of theupper region 3211 of rear 3210 can be 0.115 inch (0.292 cm), 0.125 inch(0.318 cm), 0.135 inch (0.343 cm), 0.145 inch (0.368 cm), 0.155 inch(0.394 cm), 0.165 inch (0.419 cm), 0.175 inch (0.445 cm), 0.185 inch(0.470 cm), 0.195 (0.495 cm), or 0.250 inch (0.635 cm). In someembodiments, the height 3480 of rear wall 3423 of the upper region 3211of rear 3210 can range from 0.150 inch (0.381 cm) to 0.210 inch (0.533cm). In some embodiments, the height 3480 of rear wall 3423 of the upperregion 3211 of rear 3210 can be 0.166 inch (0.422 cm). In someembodiments, the height 3480 of rear wall 3423 of upper region 3211 ofrear 3210 can range from 3% to 15% of the height of the golf club head3200.

The height 3480 of rear wall 3423 of the upper region 3211 of rear 3210,as described herein, allows cavity 3230 to absorb at least a portion ofthe stress on strikeface 3212 during impact with a golf ball. A golfclub head having a rear wall height greater than rear wall height 3480described herein would absorb less stress (and allow less strikefacedeflection) in impact than golf club head 3200 described herein, due toincreased dispersion of the impact stress along the top rail prior toreaching the cavity.

In some embodiments, cavity 3230 is located above a lower region 3213 ofrear 3210 and is defined at least in part by upper region 3211 and lowerregion 3213 of rear 3210. Cavity 3230 comprises top wall 3219, and backwall 3421. A first reference point 3422 is located between the top rail3215 and rear wall 3423. A second reference point 3482 is locatedbetween rear wall 3423 and top wall 3219. A first inflection point 3486is located between top wall 3219 of cavity 3230 and back wall 3421. Athird reference point 3424 is point located on top wall 3219 closest tothe strikeface 3212. First reference point 3422 and second referencepoint 3482 create a first reference line 3429. Second reference point3482 and third reference point 3424 create a second reference line 3425.Third reference point 3424 and first inflection point 3486 create athird reference line 3426.

Golf club head 3200 further comprises a height 3488 of top wall 3219,measured parallel to strikeface 3212 and from the second reference point3482 to first inflection point 3486. In many embodiments, height 3488can range from 0.100 inch (0.254 cm) to 0.700 inch (1.778 cm). Forexample, height 3488 can be 0.100 inch (0.254 cm), 0.150 inch (0.381cm), 0.200 inch (0.508 cm), 0.250 inch (0.635 cm), 0.300 inch (0.762cm), 0.350 inch (0.899 cm), 0.400 inch (1.016 cm), 0.450 inch (1.143cm), 0.500 inch (1.270 cm), 0.550 inch (1.397 cm), 0.600 inch (1.524cm), 0.650 inch (1.651 cm), or 0.700 inch (1.778 cm). In manyembodiments, height 3488 can range from 0.300 inch (0.762 cm) to 0.550inch (1.397 cm). In some embodiments, height 3488 of top wall 3219 canbe 0.300 inch (0.762 cm), 0.330 inch (0.838 cm), 0.360 inch (0.914 cm),0.390 inch (0.991 cm), 0.420 inch (1.067 cm), 0.450 inch (1.143 cm),0.480 inch (1.219 cm), 0.510 inch (1.295 cm), or 0.540 inch (1.312 cm).

In many embodiments, second reference point 3482 can range from 0.075inch (0.191 cm) to 1.00 inches (2.54 cm) or 0.150 inch (0.381 cm) to0.180 inches (0.457 cm) to apex 3428 of top rail 3215. For example, thesecond reference point 3482 can be 0.075 inch (0.191 cm), 0.095 inch(0.241 cm), 0.115 inch (0.292 cm), 0.135 inch (0.343 cm), 0.155 inch(0.394 cm), 0.175 inch (0.445 cm), 0.190 inch (0.483 cm), or 1.000 inch(2.54 cm) below the apex 3428 of top rail 3215.

In many embodiments, top wall 3219 of cavity 3230 can be substantiallyparallel to strikeface 3212. In other embodiments, top wall 3219 is notsubstantially parallel to strikeface 3212. In some embodiments, top wall3219 of cavity 3230 is substantially parallel to rear wall 3423 of upperregion 3211 of rear 3210. In a number of embodiments, a portion of topwall 3219 extends away from top rail 3215 toward strikeface 3212 fromsecond reference point 3482 to third reference point 3424. In someembodiments, the portion of top wall 3219 extending away from top rail3215 toward strikeface 3212 from second reference point 3482 to thirdreference point 3424 can be straight, curved upward, or curved downward.In many embodiments, a portion of top wall 3219 of cavity 3230 is angledaway from strikeface 3212 from third reference point 3424 to firstinflection point 3486. In some embodiments, the portion of top wall 3219angled away from strikeface 3212 from third reference point 3424 tofirst inflection point 3486 can be straight, curved upward, or curveddownward. This orientation of top wall 3219 creates a buckling point,hinge point or plastic hinge to direct the stress of impact towardcavity 3230 and to allow increased flexing of strikeface 3212 duringimpact.

Lower region 3213 of rear 3210 comprises back wall 3421 of cavity 3230and lower exterior wall 3427. In some embodiments, back wall 3421 ofcavity 3230 can have a back wall length 3490 measured from firstinflection point 3486 to a second inflection point 3492 located betweenthe back wall 3421 and the lower exterior wall 3427. In a number ofembodiments, back wall length 3490 can range from 0.100 inch (0.254 cm)to 0.350 inch (0.889 cm). In many embodiments, back wall length 3490 canbe 0.100 inch (0.254 cm), 0.125 inch (0.318 cm), 0.150 inch (0.381 cm),0.175 inch (0.445 cm), 0.200 inch (0.508 cm), 0.225 inch (0.572 cm),0.250 inch (0.635 cm), 0.275 inch (0.699 cm), 0,300 inch (0.762 cm),0.325 inch (0.826 cm), or 0.350 inch (0.889 cm).

In some embodiments, a lower angle 3451 can be measured from between theback wall 3421 and the lower exterior wall 3427. In some embodiments,lower angle 3451 can be less than 180 degrees. In a number ofembodiments, lower angle 3451 can range from 30 degrees to 180 degrees.In various embodiments, lower angle 3451 can range from 70 degrees to130 degrees. In some embodiments, lower angle 3451 can be 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, or 130degrees.

In some embodiments, an inflection angle 3496 measured from thirdreference line 3426 to back wall 3421 can range from 70 degrees to 150degrees. In some embodiments, inflection angle 3496 can range from 90degrees to 130 degrees. In some embodiments, inflection angle 3496 canbe 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees, 120degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145degrees, or 150 degrees. In many embodiments, inflection angle 3496allows first inflection point 3486 to act as a buckling point or plastichinge upon golf club head 3200 impacting the golf ball at strikeface3212. In some embodiments, the wall thickness at the first inflectionpoint 3486 can be thinner than at the top wall 3219 and back wall 3421.

In many embodiments, first inflection point 3486, adjacent to back wall3421 can range from 0.20 inch (0.508 cm) to 1.0 inch (2.54 cm), or 0.5inch (1.27 cm) to 0.7 inch (1.778 cm) below the apex 3428 of top rail3215. For example, the first inflection point 3486 can be 0.20 inch(0.508 cm), 0.25 inch (0.635 cm), 0.30 inch (0.762 cm), 0.35 inch (0.889cm), 0.40 inch (1.016 cm), 0.45 inch (1.143 cm), 0.50 inch (1.27 cm),0.55 inch (1.397 cm), 0.60 inch (1.524 cm), 0.65 inch (1.651 cm), 0.70inch (1.778 cm), 0.75 inch (1.905 cm), 0.80 inch (2.032 cm), 0.85 inch(2.159 cm), 0.90 inch (2.286 cm), 0.95 inch (2.413 cm), or 1.0 inch(2.54 cm) below the apex 3428 of top rail 3215. In some embodiments, themaximum height of the back wall 3421, measured perpendicular to a ground3403 when golf club head 3200 is at address, from a lowest point of sole3206 to first inflection point 3486, can range from 0.25 inch (0.635 cm)to 3 inches (7.62 cm), or 0.50 inch (1.27 cm) to 2 inches (5.08 cm). Forexample, the first inflection point 3486 can be 0.25 inch (0.635 cm),0.375 inch (0.953 cm), 0.5 inch 1.27 cm), 0.625 inch (1.59 cm), 0.75inch (1.91 cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125 inches(2.88 cm), 1.25 inches (3.18 cm), 1.375 inches (3.49 cm), 1.5 inches(3.81 cm), 1.625 inches (4.12 cm), 1.75 inches (4.45 cm), 1.875 inches(4.76 cm), 2.0 inches (5.08 cm), 2.125 inches (5.40 cm), 2.25 inches(5.71 cm), 2.375 inches (6.03 cm), 2.5 inches (6.35 cm), 2.625 inches(6.67 cm), 2.75 inches (7.00 cm), 2.875 inches (7.30 cm) or 3.0 inches(7.62 cm) above a lowest point of sole 3206 to the ground 3403 when golfclub head 3200 is at address.

In some embodiments, a back wall angle 3405 measured from back wall 3421to ground plane 3403 can range from 15 degrees to 45 degrees. In someembodiments, back wall angle 3405 can be 15 degrees, 16 degrees, 17degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22 degrees, 23degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

In some embodiments as illustrated in FIG. 32, cavity 3230 can furthercomprise at least one channel 3239. In many embodiments, channel 3239extends from heel region 3202 to toe region 3204. Channel 3239 comprisesa channel width measured from second reference point 3482 to top wall3219 substantially parallel to ground plane 3403, where channel widthcan vary in a direction from top rail 3215 to sole 3206. In someembodiments, a maximum channel width 3432, measured from firstinflection point 3486 to second reference point 3482 substantiallyparallel to ground plane 3403, can be substantially constant throughoutthe channel 3230 from heel region 3202 to toe region 3204. In someembodiments as illustrated in FIG. 34, maximum channel width 3432 canrange from 0.039 inch (1 mm) to 0.590 inch (15 mm), or 0.150 inch (3.81mm) to 0.400 inch (10.16 mm). For example, maximum channel width 3432can be 0.039 inch (1.0 mm), 0.079 inch (2 mm), 0.12 inch (3 mm), 0.16inch (4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31inch (8 mm), 0.39 inch (10 mm), or 0.59 inch (15 mm). In otherembodiments, a channel toe region width of channel 3239 is less than achannel heel region width of channel 3239. In other embodiments, thechannel heel region width is less than the channel toe region width. Inother embodiments, a channel middle region width of channel 3239 can beless than at least one of the channel heel region width or the channeltoe region width. In other embodiments, the channel middle region widthcan be greater than at least one of the channel heel region width or thechannel toe region width. In some embodiments, channel 3239 issymmetrical from heel to toe. In other embodiments, channel 3239 isnon-symmetrical. In other embodiments, channel 3239 can further compriseat least two partial channels. In some embodiments, channel 3239 cancomprise a series of partial channels interrupted by one or morebridges. In some embodiments, the one or more bridges can beapproximately the same thickness as the thickness of upper region 3211of top rail 3215.

Maximum channel width 3432, as described herein, allows absorption ofstress from strikeface 3212 on impact. A golf club head having a channelwidth less than the maximum channel width 3432 described here (e.g., agolf club head with a less pronounced cavity) would allow less stressabsorption from the strikeface on impact (due to less material on theupper region 3211 of rear 3210), and therefore would experience lessstrikeface deflection than golf club head 3200 described herein.

In many embodiments, back cavity 3230 further comprises a cavity angle3435. Back cavity angle 3435 is measured from first reference line 3429to second reference line 3425. In many embodiments, back cavity angle3435 can range from 15 degrees to 80 degrees. In some embodiments, backcavity angle 3435 can be 15 degrees, 20 degrees, 25 degrees, 30 degrees,35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees,65 degrees, 70 degrees, 75 degrees, or 80 degrees.

FIG. 35 illustrates a view of top rail 3215 and a portion of rear 3210of the cross-section of golf club head 3200 of FIG. 32 different fromcross-section of golf club head 1200 as shown in FIG. 13. In manyembodiments, golf club head 3200 comprises a rear angle 3540, a top railangle 3545, and a strikeface angle 3550. Rear angle 3540 is measuredfrom second reference line 3425 to rear wall 3423 of upper region 3211.In many embodiments, rear angle 3540 can range from 70 degrees to 140degrees. In some embodiments, rear angle 3540 can be 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 100 degrees, 105 degrees,110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135degrees, or 140 degrees. Top rail angle 3545 is measured from rear wall3423 of upper region 3211 to top rail 3215. In many embodiments, toprail 3545 can range from 35 degrees to 120 degrees or 70 degrees to 110degrees. In some embodiments, top rail angle 3545 can be 35 degrees, 40degrees, 45 degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100degrees, 105 degrees, 110 degrees, 115 degrees, or 120 degrees.Strikeface angle 3550 is measured from strikeface 3212 to top rail 3215.In many embodiments, strikeface angle 3550 can range from 70 degrees to160 degrees or 70 degrees to 110 degrees. In some embodiments,strikeface angle 3550 can be 70 degrees, 75 degrees, 80 degrees, 90degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees,120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145degrees, 150 degrees, 155 degrees, or 160 degrees.

Upper region 3211 further comprises a minimum gap 3590 measured fromthird reference point 3424 of an inner surface 3419 of top wall 3219 toan inner surface 3419 of strikeface 3212, perpendicular to strikeface3212. In some embodiments, minimum gap 3590 can range from 0.079 inch (2mm) to 0.24 inch (6 mm). For example, the minimum gap 3590 can be 0.079inch (2 mm), 0.118 inch (3 mm), 0.16 inch (4 mm), 0.197 inch (5 mm) or0.24 inch (6 mm). In other embodiments, the minimum gap 3590 can rangefrom 0.118 inch (3 mm) to 0.16 inch (4 mm). In some embodiments, theminimum gap 3590 can be 0.135 inch (3.429 mm).

FIG. 36 illustrates a simplified cross-sectional view of golf club head3200, similar to the detailed cross-section of golf club head 3200illustrated in FIG. 34. Golf club head 3200 include cavity 3230, upperregion 3211, lower region 3213, and exterior surface 3203. In manyembodiments, a maximum upper distance 3692 measured as the perpendiculardistance from exterior surface 3203 of strikeface 3212 to exteriorsurface 3203 of second reference point 3482 of upper region 3211 canrange from 0.20 inch to 0.59 inch (5 mm to 15 mm). For example, maximumupper distance 3692 can be 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch(7 mm), 0.31 inch (8 mm), 0.35 inch (8.89 mm), 0.39 inch (10 mm), 0.43inch (11 mm), 0.47 inch (12 mm), 0.51 inch (13 mm), 0.55 inch (14 mm),or 0.59 inch (15 mm). In some embodiments, maximum upper distance 3692can be 0.348 inch (9.09 mm). Further, a minimum upper distance 3694measured as the perpendicular distance from exterior surface 3203 ofstrikeface 3212 to exterior surface 3203 of third reference point 3424can range from 0.10 inch to 0.47 inch (0.54 mm to 12 mm). For example,minimum upper distance 3694 can be 0.10 inch (2.54 mm), 0.16 inch (4mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch (8mm), 0.35 inch (9 mm), 0.39 inch (10 mm), 0.43 inch (11 mm), or 0.47inch (12 mm). In some embodiments, minimum upper distance 3694 can be0.309 inch (7.85 mm). Further still, a maximum lower distance 3696measured as the perpendicular distance from exterior surface 3203 ofstrikeface 3212 to exterior surface 3203 of a fourth reference point3420 located between the lower exterior wall 3427 and the sole 3206 canrange from 0.670 inch to 0.98 inch (17 mm to 25 mm). For example,maximum lower distance 3696 can be 0.670 inch (17 mm), 0.709 inch (18mm), 0.748 inch (19 mm), 0.787 inch (20 mm), 827 inch (21 mm), 0.866inch (22 mm), 0.906 inch (23 mm), 0.945 inch (24 mm), or 0.98 inch (25mm). In some embodiments, maximum lower distance 3696 can be 0.863 inch(21.9 mm). In many embodiments, maximum lower distance 3696 is greaterthan maximum upper distance 3692 and maximum upper distance 3692 isgreater than minimum upper distance 3694.

In many embodiments, cavity 3230 can provide an increase in golf ballspeed over golf club head 1200, or other standard golf club heads, canreduce the spin rate of standard hybrids club heads, and can increasethe launch angle over both the standard hybrid and iron club heads. Inmany embodiments, the shape of cavity 3230 determines the level ofspring and timing of the response of golf club head 3200. When the golfclub ball impacts strikeface 3212 of club head 3200 with cavity 3230,strikeface 3212 springs back like a drum, and a rear 3210 bends in acontrolled buckle manner. In many embodiments, top rail 3215 can absorbmore stress over greater volumetric space than a top rail in a golf clubhead without cavity 3230. The length, depth and width of cavity 3230 canvary. These parameter provide control regarding how much spring back ispresent in the overall design of club head 3200.

Upon impact with the golf ball, strikeface 3212 can bend inward at agreater distance than on a golf club without cavity 3230. In someembodiments, strikeface 3212 has a 10% to a 50% greater deflection thana strikeface on a golf club head without cavity 3230. In someembodiments, strikeface 3212 has a 5% to 40% or a 10% to a 20% greaterdeflection than a strikeface on a golf club head without cavity 3230.For example, strikeface 3212 can have a 5%, 10%, 15%, 20%, 25%, 30%,35%, or 40% greater deflection than a strikeface on a golf club headwithout cavity 3230. In many embodiments, there is both a greaterdistance of retraction by strikeface 3212 due to the hinge and bendingof cavity 3230 over a standard strikeface that does not have a backportion of the club with the cavity.

In many embodiments, the face deflection is greater with club head 3200having cavity 3230, as a greater buckling occurs at first inflectionangle 3486 of top wall 3219 upon impact with a golf ball. Cavity 3230,however, provides a greater dispersion of stress along top rail 3215,rear wall 3423, and top wall 3219, and the spring back force istransferred from cavity 3230 and first inflection point 3486 of top wall3219 to strikeface 3212. A standard top rail, rear wall and top wallwithout a cavity does not have this hinge/buckling effect, nor does itabsorb a high level of stress over a large volumetric area of the toprail, rear wall and top wall. Therefore, the standard strikeface doesnot contract and then recoil as much as strikeface 3212. Further, both alarger region of srikeface 3212, top rail 3215, rear wall 3423, and topwall 3219 absorb more stress than the same crown region of a standardgolf club head with a standard top rail, top wall and no cavity. In manyembodiments, although there is greater stress along a greater area abovecavity 3230 that the same area in a standard club without the cavity,the durability of the club head with without the cavity is the same. Byadding more spring to the back end of the club (due to inwardinclination of a portion of top wall 3219 toward strikeface 3212), moreforce is displace throughout the volume of the structure. The stress isobserved over a greater area of strikeface 3212, top rail 3215, rearwall 3423, and top wall 3219 of golf club head 3200. Peak stresses canbe seen in the standard top rail club head. However, more peak stressesare seen in golf club head 3200, but distributed over a large volume ofthe material. The hinge and bend regions of golf club head 3200 (i.e.,the region above cavity 3230 and cavity 3230 itself) will not deform aslong as the stress does not meet the critical buckling threshold. Cavity3230 and its placement can be design to be under the critical K value ofthe buckling threshold.

As shown in FIG. 36, a further deflection feature of the golf club head3200 can be the uniform thinned region 3660, located at the sole 3206and stretching between the rear 3210 of the body 3201 and the strikeface3212, toward a cascading sole portion of the sole (as described ingreater detail below). The uniform thinned region 3660 can providemultiple benefits. First, the uniform thinned region 3660 can reducestress on the strikeface 3212 caused during impact with the golf ball.Second, the uniform thinned region 3660 can bend allowing the strikeface3212 to experience greater deflection. Third, the uniform thinned region3660 removes weight from the sole area, allowing the weight to beredistributed more toward the rear of the golf club head 3200. Atimpact, the energy imparted to the strikeface 3212 by the golf ball cancause the uniform thinned region 3660 to bend outward, which in turnincreases the strikeface 3212 deflection. After bending, the uniformthinned region 3660 rebounds back to its original position returning themajority of the energy from impact back to the golf ball. The result isthe golf club head 3200 imparts increased ball speeds and greater traveldistances to the golf ball after impact.

In some embodiments, body 3201 can comprises stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 3201can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 3212 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 3212 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 2701 can comprise the same material as strikeface3212. In some embodiments, body 2701 can comprise a different materialthan strikeface 3212.

FIG. 37 illustrates a back perspective view of an embodiment of golfclub head 3700 and FIG. 38 illustrates a back heel-side perspective viewof golf club head 3700 according to the embodiment of FIG. 37. In someembodiments, golf club head 3700 can be similar to golf club head 1000(FIG. 10), golf club head 2200 (FIG. 22), golf club head 2700 (FIG. 27),and/or golf club head 3200 (FIG. 32). Golf club head 3700 can be aniron-type golf club head. In other embodiments, golf club head 3700 canbe a hybrid-type, or a fairway wood-type golf club head. In someembodiments, golf club head 3700 does not comprise a badge or a customtuning port.

Golf club head 3700 comprises a body 3701. In some embodiments, body3701 can be similar to body 1001 (FIG. 10), body 2201 (FIG. 22), body2701 (FIG. 27), and/or body 3201 (FIG. 32). In some embodiments, thebody 3701 is hollow with an internal cavity 3716. In other embodiments,the body is at least partially hollow. In embodiments wherein body 3701is hollow or partially hollow, body 3701 can comprises a volume void ofinternal cavity 3716 ranging from 1.71 inches³ (28 cc) to 2.3 inches³(37.69 cc). In some hollow and partially hollow embodiments, body 3701can comprise a volume of 1.70 inches³ (27.86 cc), 1.80 inches³ (29.50cc), 1.90 inches³ (31.14 cc), 2.00 inches³ (32.77 cc), 2.10 inches³(34.41 cc) 2.20 inches³ (36.05 cc), or 2.30 inches³ (37.69 cc). Body3701 further comprises an exterior surface 3703, a strikeface 3712, aheel region 3702, a toe region 3704 opposite the heel region 3702, asole 3706, a top rail 3715, and a rear 3710.

Body 3701 of FIGS. 37-43 further comprises a blade length 3725, a toeedge 3726, and a strikeface end 3727. The toe edge 3726 is the farthestedge of the strikeface 3712 at the toe region 3704, and the strikefaceend 3727 is the end of the strikeface 3712 at the heel region 3702,right before the strikeface 3712 integrally curves into the hosel. Asillustrated in FIG. 43, blade length 3725 is the distance measured fromthe toe edge 3726 to the strikeface end 3727. The blade length 3725 ismeasured parallel to the flat surface of the strikeface 3712 between thetoe edge 3726 and the strikeface end 3727 at the heel end 3702 beforethe strikeface 3712 integrally curves with the hosel. The blade lengthof the body 3701 can range from 2.70 inch (6.86 cm) to 3.00 inch (7.62cm). For example, in some embodiments the body 3701 can comprise a bladelength of 2.74 inch (6.96 cm), 2.78 inch (7.06 cm), 2.82 inch (7.16 cm),2.86 inch (7.26 cm), 2.90 inch (7.37 cm), 2.94 inch (7.47 cm), 2.98 inch(7.57 cm), or 3.00 inch (7.62 cm).

The body 3701 further comprises a uniform thinned region transitioningfrom the bottom of the strikeface 3712 to the sole 3706, toward acascading sole portion of the sole (as described in greater detailbelow). In the illustrated embodiment, the uniform thinned regioncomprises a sole thickness measured perpendicular from the exteriorsurface 3703 to an interior surface 3919 at the uniform thinned region,which can remain constant from the bottom of the strikeface 3712 toadjacent the cascading sole portion of the sole. In some embodiments,the sole thickness of the uniform thinned region can be thinner than aconventional sole. For example, in some embodiments, the sole thicknessof the uniform thinned region may range from approximately 0.040 inch to0.080 inch. In other embodiments, the sole thickness of the uniformthinned region may be within the range of 0.040 inch to 0.050 inch,0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065inch to 0.080 inch. For example, the sole thickness of the uniformedthinned region can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060 inch,0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 39 illustrates a cross-section of golf club head 3700 along thecross-sectional line XXXIX-XXXIX in FIG. 37, according to oneembodiment. As seen in FIG. 39, strikeface 3712 comprises a high region3976, a middle region 3974, and a low region 3972. Rear 3710 cancomprise an upper region 3711, a lower region 3713, and a cavity 3730.

Upper region 3711 of rear 3710 comprises top rail 3715, a rear wall3923, a top wall 3719, and a back wall 3921. In many embodiments, therear wall 3923 of rear 3710 is located below and adjacent to the toprail 3715, the top wall 3719 of rear 3710 is located below and adjacentto the rear wall 3923, and the back wall 3721 is located below andadjacent to the top wall 3719. Upper region further comprises a firstreference point 3922 located between top rail 3715 and rear wall 3923, asecond reference point 3982 located between rear wall 3923 and top wall3719, a first inflection point 3986 located between top wall 3719 andback wall 3921, and a second inflection point 3992 located between theback wall 3921, and a bottom incline 3925 of the lower region 3713.First reference point 3922 and second reference point 3982 create areference line 3939 as illustrated in FIG. 40.

The top wall 3719 is angled toward the strikeface and away from the toprail 3715 in a direction toward the first inflection point 3986. Thedescribed configuration of the top wall 3719 allows increased bending ofthe top rail 3715 of the club head 3700 on impact with a golf ball,compared with a club head devoid of the described top wallconfiguration.

Cavity 3730 is located on the exterior surface 3703, below top rail 3715and rear wall 3923, above the lower region 3713 of rear 3710, and isdefined by at least in part by upper region 3711 and lower region 3713.

In some embodiments, top rail 3715 of the upper region 3711 can be aflatter and taller top rail or skirt than in irons known to one skilledin the art. The flatter and taller rail can compensate for mishits ofstrikeface 3712 to increase playability off the tee. In someembodiments, the length of top rail 3715, measured from heel region 3702to toe region 3704, can be 70% to 95% of the length of golf club head3700. In many embodiments, cavity 3730 comprises a top rail box springdesign. For some fairway iron-type golf club head embodiments, cavity3730 can be a reverse scoop or indentation of rear 3710 with body 3701comprising a greater thickness toward sole 3706. In many embodiments,top rail 3715 and cavity 3730 provide an increase in the overall bendingof strikeface 3712. In some embodiments, the bending of strikeface 3712can allow for a 2% to 5% increase of energy. Cavity 3730 allows forstrikeface 3712 to be thinner and allow additional overall bending.

Strikeface 3712 of body 3701 comprises a thickness 3954 measuredperpendicularly to strikeface 3712 from the exterior surface 3703 to theinterior surface 3919. The thickness 3954 of the strikeface 3712 canrange from 0.060 inch to 0.110 inch. For example, the thickness 3954 ofthe strikeface 3712 can be 0.060 inch, 0.065 inch, 0.070 inch, 0.075inch, 0.080 inch, 0.085 inch, 0.090 inch, 0.095 inch, 0.100 inch, 0.105inch, or 0.110 inch. In some embodiments, thickness 3954 of strikeface3712 can remain constant from heel region 3702 to toe region 3704,and/or from top rail 3715 to sole 3706. In other embodiments, thickness3954 of strikeface 3712 can vary from heel region 3702 to toe region3704, and/or from top rail 3715 to sole 3706. For example, the thickness3954 of strikeface 3712 can be greatest at a central portion ofstrikeface 3712 near the middle region 3974, and taper along theperiphery of strikeface 3712 near the high region 3976, and the lowregion 3972. In many embodiments, the center of the strikeface 3712 nearthe middle region 3974 can have a thickness 3954 of 0.100 inch and theperiphery of the strikeface 3712 can have a thickness 3954 of 0.080inch. In other examples, the thickness 3954 can increase, or decreases,or any variation thereof starting at a central region near the middleregion 3974 of strikeface 3712 and extending toward the periphery nearthe high region 3976 and the low region 3972.

Golf club head 3700 further comprises a height 3980 for rear wall 3923of upper region 3711 of rear 3710 measured from first reference point3922 to second reference point 3982. In some embodiments, height 3980 ofrear wall 3923 of upper region 3711 of rear 3710 can range from 0.115inch (0.292 cm) to 0.250 inch (0.635 cm), 0.130 inch (0.330 cm) to 0.200inch (0.508 cm), or 0.150 inch (0.381 cm) to 0.180 inch (0.457 cm). Forexample, in some embodiments, the height 3980 of rear wall 3923 of theupper region 3711 of rear 3710 can be 0.115 inch (0.292 cm), 0.125 inch(0.318 cm), 0.135 inch (0.343 cm), 0.145 inch (0.368 cm), 0.155 inch(0.394 cm), 0.165 inch (0.419 cm), 0.175 inch (0.445 cm), 0.185 inch(0.470 cm), 0.195 (0.495 cm), or 0.250 inch (0.635 cm). In someembodiments, the height 3980 of rear wall 3923 of the upper region 3711of rear 3710 can range from 0.150 inch (0.381 cm) to 0.210 inch (0.533cm). In some embodiments, the height 3980 of rear wall 3923 of the upperregion 3711 of rear 3710 can be 0.166 inch (0.422 cm). In someembodiments, the height 3980 of rear wall 3923 of upper region 3711 ofrear 3710 can range from 3% to 15% of the height of the golf club head3700.

The height 3980 of rear wall 3923 of the upper region 3211 of rear 3210,as described herein, allows cavity 3730 to absorb at least a portion ofthe stress on strikeface 3712 during impact with a golf ball. A golfclub head having a rear wall height greater than rear wall height 3980described herein would absorb less stress (and allow less strikefacedeflection) in impact than golf club head 3700 described herein, due toincreased dispersion of the impact stress along the top rail prior toreaching the cavity.

Rear wall 3923 further comprises a thickness measured perpendicularlyfrom the exterior surface 3703 to the interior surface 3919 of the rearwall 3923. The thickness of the rear wall 3923 can range from 0.037 inchto 0.058 inch, 0.037 inch to 0.048 inch, or 0.042 inch to 0.058 inch.For example, the thickness of the rear wall 3923 can be 0.037 inch,0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.052 inch, 0.055 inch,or 0.058 inch. The thickness of the rear wall 3923 can aid in stressdistribution as well as increase the bending of the strikeface 3712.

In many embodiments, second reference point 3982 of upper region 3711 ofrear 3710 can have a distance ranging from 0.150 inch (0.381 cm) to 1.00inch (2.54 cm), 0.150 inch (0.381 cm) to 0.350 inches (0.457 cm), 0.300inch (0.457 cm) to 0.500 inch (1.27 cm), 0.450 inch (1.14 cm) to 0.650inch (1.65 cm), 0.600 inch (1.52 cm) to 0.800 inch (2.03 cm), or 0.750inch (1.91 cm) to 1.00 inch (2.54 cm) from apex 3928 of top rail 3715.For example, the second reference point 3982 of upper region 3711 can be0.150 inch (0.381 cm), 0.450 inch (1.14 cm), 0.600 inch (1.52 cm), 0.750inch (1.91 cm), 0.900 inch (2.29 cm), or 1.000 inch (2.54 cm) below theapex 3428 of top rail 3215.

Golf club head 3700 further comprises a length 3988 of top wall 3719 ofupper region 3711, measured from the second reference point 3982 tofirst inflection point 3986. In many embodiments, top wall length 3988can range from 0.030 inch (0.076 cm) to 0.100 inch (0.254 cm). In manyembodiments, top wall length 3988 can range from 0.030 inch (0.076 cm)to 0.050 inch (0.127 cm), 0.040 inch (0.102 cm) to 0.060 inch (0.152cm), 0.050 (0.127 cm) to 0.080 inch (0.203 cm), or 0.070 inch (0.178 cm)to 0.100 inch (0.254 cm). For example, top wall length 3988 can be 0.030inch (0.076 cm), 0.035 inch (0.089 cm), 0.040 inch (0.102 cm), 0.045inch (0.114 cm), 0.050 inch (0.127 cm), 0.055 inch (0.140 cm), 0.060inch (0.152 cm), 0.065 inch (0.165 cm), 0.070 inch (0.178 cm), 0.075inch (0.191 cm), 0.080 inch (0.203 cm), 0.085 inch (0.216 cm), 0.090inch (0.229 cm), 0.095 inch (0.241 cm), or 0.100 inch (0.254 cm).

In a number of embodiments, a portion of top wall 3719 of upper region3711 extends away from rear wall 3923 at second reference point 3982,toward strikeface 3712 at first inflection point 3986. In someembodiments, the portion of top wall 3719 extending away from rear wall3923 toward strikeface 3712 can be straight, curved upward, or curveddownward. This orientation of top wall 3719 creates a buckling point,hinge point or plastic hinge to direct the stress of impact towardcavity 3730 and to allow increased flexing of strikeface 3712 duringimpact.

The first inflection point 3986 of the upper region 3711, can have adistance from the first reference point 3922 ranging from 0.20 inch(0.508 cm) to 1.0 inch (2.54 cm), or 0.5 inch (1.27 cm) to 0.7 inch(1.778 cm). For example, the first inflection point 3986 can be 0.20inch (0.508 cm), 0.25 inch (0.635 cm), 0.30 inch (0.762 cm), 0.35 inch(0.889 cm), 0.40 inch (1.016 cm), 0.45 inch (1.143 cm), 0.50 inch (1.27cm), 0.55 inch (1.397 cm), 0.60 inch (1.524 cm), 0.65 inch (1.651 cm),0.70 inch (1.778 cm), 0.75 inch (1.905 cm), 0.80 inch (2.032 cm), 0.85inch (2.159 cm), 0.90 inch (2.286 cm), 0.95 inch (2.413 cm), or 1.0 inch(2.54 cm) below the first reference point 3922.

In some embodiments, upper region 3711 further comprises an inflectionangle 3996 measured from top wall 3719 to back wall 3921, whereininflection angle 3996 can range from 70 degrees to 150 degrees. In someembodiments, inflection angle 3996 of upper region can range from 90degrees to 130 degrees. In some embodiments, inflection angle 3996 ofupper region can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees,120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145degrees, or 150 degrees. In many embodiments, inflection angle 3996 ofupper region allows first inflection point 3986 to act as a bucklingpoint or plastic hinge upon golf club head 3700 impacting the golf ballat strikeface 3712. In some embodiments, the wall thickness at the firstinflection point 3986 can be thinner than at the top wall 3719 and backwall 3921.

In some embodiments, back wall 3921 of cavity 3730 of upper region 3711can have a back wall length 3990 measured from first inflection point3986 to second inflection point 3992. In a number of embodiments, backwall length 3990 can range from 0.100 inch (0.254 cm) to 0.350 inch(0.889 cm). In many embodiments, back wall length 3990 can be 0.100 inch(0.254 cm), 0.125 inch (0.318 cm), 0.150 inch (0.381 cm), 0.175 inch(0.445 cm), 0.200 inch (0.508 cm), 0.225 inch (0.572 cm), 0.250 inch(0.635 cm), 0.275 inch (0.699 cm), 0,300 inch (0.762 cm), 0.325 inch(0.826 cm), or 0.350 inch (0.889 cm).

The back wall 3921 of the cavity 3730 can further comprise a thicknessmeasured perpendicularly from the interior surface 3919 to the exteriorsurface 3703 of the back wall 3921. The thickness of the back wall 3921can range from 0.028 inch to 0.039 inch, 0.028 inch to 0.032 inch, or0.032 inch to 0.039 inch. For example, the thickness of the back wall3921 can be 0.028 inch, 0.030 inch, 0.032 inch, 0.034 inch, 0.035 inch,0.037 inch, or 0.039 inch. The thickness of the back wall 3921 can helpdistribute stress and increase the bending of the strikeface 3712.

In some embodiments, the maximum height of the back wall 3921 of theupper region 3711, measured perpendicular to a ground plane 3903 whengolf club head 3700 is at address, to first inflection point 3986, canrange from 0.25 inch (0.635 cm) to 3 inches (7.62 cm), or 0.50 inch(1.27 cm) to 2 inches (5.08 cm). For example, the first inflection point3986 can be 0.25 inch (0.635 cm), 0.375 inch (0.953 cm), 0.5 inch 1.27cm), 0.625 inch (1.59 cm), 0.75 inch (1.91 cm), 0.825 inch (2.10 cm),1.0 inch (2.54 cm), 1.125 inches (2.88 cm), 1.25 inches (3.18 cm), 1.375inches (3.49 cm), 1.5 inches (3.81 cm), 1.625 inches (4.12 cm), 1.75inches (4.45 cm), 1.875 inches (4.76 cm), 2.0 inches (5.08 cm), 2.125inches (5.40 cm), 2.25 inches (5.71 cm), 2.375 inches (6.03 cm), 2.5inches (6.35 cm), 2.625 inches (6.67 cm), 2.75 inches (7.00 cm), 2.875inches (7.30 cm) or 3.0 inches (7.62 cm) above a lowest point of sole3706 to the ground plane 3903 when golf club head 3700 is at address.

In many embodiments, second inflection point 3992 of cavity 3730 ofupper region 3711, adjacent to bottom incline 3925 of lower region 3713,can have a distance from apex 3928 of top rail 3715 ranging from atleast 0.25 inch (0.635 cm) to 2.0 inches (5.08 cm), or 0.5 inch (1.27cm) to 1.5 inches (3.81 cm). For example, the second inflection point3992 can be at least 0.25 inch (0.635 cm), 0.5 inch (1.27 cm), 0.75 inch(1.91 cm), 1.0 inch (2.53 cm), 1.25 inches (3.18 cm), 1.75 inches (4.45cm), or 2.0 inches (5.08 cm) below the apex 3928 of top rail 3715.

In some embodiments as illustrated in FIG. 37, cavity 3730 of upperregion 3711 can comprise at least one channel 3739. In many embodiments,channel 3739 extends from heel region 3702 to toe region 3704. Channel3739 comprises a channel width 3932 measured from back wall 3921 to thesecond reference point 3982 substantially parallel to ground plane 3903,where channel width can vary in a direction from top rail 3215 to sole3206. In some embodiments as illustrated in FIG. 37, channel width 3932can range from 0.039 inch (1 mm) to 0.590 inch (15 mm), or 0.150 inch(3.81 mm) to 0.400 inch (10.16 mm). For example, channel width 3932 canbe 0.039 inch (1.0 mm), 0.079 inch (2 mm), 0.12 inch (3 mm), 0.16 inch(4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch(8 mm), 0.39 inch (10 mm), or 0.59 inch (15 mm). In other embodiments, achannel toe region width of channel 3739 is less than a channel heelregion width of channel 3739. In other embodiments, the channel heelregion width is less than the channel toe region width. In otherembodiments, a channel middle region width of channel 3739 can be lessthan at least one of the channel heel region width or the channel toeregion width. In other embodiments, the channel middle region width canbe greater than at least one of the channel heel region width or thechannel toe region width. In some embodiments, channel 3739 issymmetrical from heel to toe. In other embodiments, channel 3739 isnon-symmetrical. In other embodiments, channel 3739 can further compriseat least toe partial channels. In some embodiments, channel 3739 cancomprise a series of partial channels interrupted by one or morebridges. In some embodiments, the one or more bridges can beapproximately the same thickness as the thickness of top rail 3715.

Channel width 3932, as described herein, allows absorption of stressfrom strikeface 3712 on impact. A golf club head having a channel widthless than the channel width 3932 described here (e.g., a golf club headwith a less pronounced cavity) would allow less stress absorption fromthe strikeface on impact (due to less material on the upper region 3711of rear 3710), and therefore would experience less strikeface deflectionthan golf club head 3700 described herein.

In many embodiments, back cavity 3730 further comprises a back cavityangle 3935. Back cavity angle 3935 is measured from reference line 3939to top wall 3719. In many embodiments, back cavity angle 3935 can rangefrom 5 degrees to 80 degrees. In some embodiments, back cavity angle3935 can be 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees,30 degrees, 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55 degrees,60 degrees, 65 degrees, 70 degrees, 75 degrees, or 80 degrees.

In some embodiments, back wall 3921 of cavity 3730 of upper region 3711can further comprise a planar surface. In other embodiments, at least aportion of back wall 3921 can comprise a protrusion 3940 extendingoutward, away from strike face 3712. At least a portion of back wall3921 comprising protrusion 3940 can range from 15% to 100%. For example,at least 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%,75%, 80%, 85%, 90%, 95%, or 100% of back wall 3921 can compriseprotrusion 3940. Protrusion 3940 can be positioned on at least a portionof back wall 3921 closer to toe region 3704, closer to heel region 3702,closer to lower exterior wall 3927, closer to top wall 3719, or centeredon the back wall 3921. Protrusion 3940 comprises a length 3942, measuredfrom heel region 3702 to toe region 3704, and a width 3944, measuredfrom top rail 3715 to sole 3706.

The protrusion 3940 can comprise a thickness measured perpendicularlyfrom the interior surface 3919 to the exterior surface 3703 of theprotrusion 3940. The thickness of the protrusion 3940 can range from0.028 inch to 0.045 inch, 0.028 inch to 0.032 inch, 0.032 inch to 0.039inch, or 0.039 inch to 0.045 inch. For example, the thickness of theback wall 3921 can be 0.028 inch, 0.030 inch, 0.032 inch, 0.034 inch,0.035 inch, 0.037 inch, 0.039 inch, 0.041 inch, 0.043 inch, or 0.045inch. The thickness of the protrusion 3940 can help distribute stressand increase the bending of the strikeface 3712.

FIG. 40 illustrates a view of top rail 3715 and a portion of rear 3710of the cross-section of golf club head 3700 of FIG. 37, along across-sectional line XXXIX-XXXIX in FIG. 37 that is similar to thecross-section of FIG. 39. In many embodiments, golf club head 3700comprises a rear angle 4040, a top rail angle 4045, and a strikefaceangle 4050. Rear angle 4040 is measured from top wall 3719 to rear wall3923 of upper region 3711. In many embodiments, rear angle 4040 canrange from 70 degrees to 140 degrees. In some embodiments, rear angle4040 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees,100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125degrees, 130 degrees, 135 degrees, or 140 degrees. Top rail angle 4045is measured from rear wall 3923 of upper region 3711 to top rail 3715.In many embodiments, top rail angle 4045 can range from 35 degrees to120 degrees or 70 degrees to 110 degrees. In some embodiments, top railangle 4045 can be 35 degrees, 40 degrees, 45 degrees, 50 degrees, 55degrees, 60 degrees, 65 degrees, 70 degrees, 75 degrees, 80 degrees, 85degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees,115 degrees, or 120 degrees. Strikeface angle 4050 is measured fromstrikeface 3712 to top rail 3715. In many embodiments, strikeface angle4050 can range from 70 degrees to 160 degrees or 70 degrees to 110degrees. In some embodiments, strikeface angle 4050 can be 70 degrees,75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees, 105degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155degrees, or 160 degrees.

The upper region 3711 further comprises a minimum gap 4090 measured as aperpendicular distance from an inner surface of the cavity at the firstinflection point 3986 to the inner surface 3919 of strikeface 3712. Insome embodiments, minimum gap 4090 can range from 0.079 inch (2 mm) to0.24 inch (6 mm). For example, minimum gap 4090 can be 0.079 inch (2mm), 0.118 inch (3 mm), 0.16 inch (4 mm), 0.197 inch (5 mm) or 0.24 inch(6 mm). In other embodiments, minimum gap 4090 can range from 0.118 inch(3 mm) to 0.16 inch (4 mm). In some embodiments, minimum gap 4090 can be0.135 inch (3.429 mm).

Lower region 3713 of rear 3710 of body 3701 comprises the bottom incline3925, and a lower exterior wall 3927. The lower exterior wall 3927 islocated below and adjacent the bottom incline 3925. A third inflectionpoint 3994 is located between the bottom incline 3925 and the lowerexterior wall 3927. A third reference point 3920 is located betweenlower exterior wall 3927 and sole 3706.

A top portion of the lower exterior wall 3927 of the lower region 3713can comprise a thickness. The thickness of the top portion of the lowerexterior wall 3927 can be measured perpendicular from the interiorsurface 3919 to the exterior surface 3703 of the top portion of thelower exterior wall 3927. The thickness of the top portion of the lowerexterior wall 3827 can range from 0.037 inch to 0.058 inch, 0.037 inchto 0.048 inch, or 0.042 inch to 0.058 inch. For example, the thicknessof the top portion of the lower exterior wall 3827 can be 0.037 inch,0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.052 inch, 0.055 inch,or 0.058 inch. The thickness of the top portion of the lower exteriorwall 3827 can aid in stress distribution as well as increase the bendingof the strikeface 3712.

In some embodiments, bottom incline 3925 of lower region 3713 comprisesa bottom incline length 3929. Bottom incline length 3929 is measuredfrom second inflection point 3992 to the third inflection point 3994. Ina number of embodiments, bottom incline length 3994 can range from 0.010inch (0.025 cm) to 0.210 inch (0.533 cm), 0.010 inch (0.025 cm) to 0.050inch (0.127 cm), 0.050 inch (0.127 cm) to 0.100 inch (0.254 cm), 0.100inch (0.254 cm) to 0.150 inch (0.381 cm), or 0.150 inch (0.381 cm) to0.210 inch (0.533 cm). In many embodiments, bottom incline length 3929can be 0.010 inch (0.025 cm), 0.030 inch (0.076 cm), 0.050 inch (0.127cm), 0.070 inch (0.178 cm), 0.090 inch (0.229 cm), 0.110 inch (0.279cm), 0.130 inch (0.330 cm), 0.150 inch (0.381 cm), 0.160 inch (0.406cm), 0.170 inch (0.432 cm), 0.180 inch (0.457 cm), 0.190 inch (0.483cm), 0.200 inch (0.508 cm), or 0.210 inch (0.533 cm). In someembodiments, the bottom incline length 3929 can vary from heel region3702 to toe region 3704. In other embodiments, the bottom incline length3929 can remain constant from heel region 3702 to toe region 3704.

In some embodiments, the maximum height of bottom incline 3925, measuredperpendicular from ground plane 3903 when body 3701 is at address, tosecond inflection point 3992, can be 0.25 inches (0.635 cm) to 3 inches(7.62 cm), 0.05 inch (1.27 cm) to 2 inches (5.08 cm) above ground 3903.For example, the second inflection point 3992 can be 0.25 inch (0.635cm), 0.375 inch (0.953 cm), 0.5 inch (1.27 cm), 0.625 inch (1.59 cm),0.75 inch (1.91 cm), 0.825 inch (2.10 cm), 1.0 inch (2.54 cm), 1.125inches (2.88 cm), 1.25 inches (3.18 cm), 1.375 inches (3.49 cm), 1.5inches (3.81 cm), 1.625 inches (4.12 cm), 1.75 inches (4.45 cm), 1.875inches (4.76 cm), 2.0 inches (5.08 cm), 2.125 inches 5.40 cm), 2.25inches (5.71 cm), 2.375 inches (6.03 cm), 2.5 inches (6.35 cm), 2.625inches (6.67 cm), 2.75 inches (7.00 cm), 2.875 inches (7.30 cm), or 3.0inches (7.62 cm) above ground 3903.

In some embodiments, lower region 3713 further comprises a lower angle3951 measured from between the bottom incline 3925 of lower region 3713and lower exterior wall 3927 of lower region 3710, as illustrated inFIG. 41. In some embodiments, lower angle 3951 can be less than 180degrees. In a number of embodiments, lower angle 3951 can be 30 degreesto 160 degrees, or 70 degrees to 130 degrees. For example, lower angle3951 can be 30 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees,80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130degrees, 140 degrees, 150 degrees, or 160 degrees.

In some embodiments, lower region 3713 further comprises a bottomincline angle 3905 measured from bottom incline 3925 to ground 3903.Bottom incline angle 3905 can range from 15 degrees to 45 degrees. Insome embodiments, bottom incline angle 3905 can be 15 degrees, 16degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21 degrees, 22degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or 45 degrees.

FIG. 41 illustrates a simplified cross-sectional view of golf club head3700, similar to the detailed cross-section of golf club head 3700illustrated in FIG. 39. Golf club head 3700 include cavity 3730, upperregion 3711, lower region 3713, and exterior surface 3703. In manyembodiments, a maximum upper distance 4192 measured as the perpendiculardistance from exterior surface 3703 of strikeface 3712 to exteriorsurface 3703 of second reference point 3982 of upper region 3711 canrange from 0.20 inch to 0.59 inch (5 mm to 15 mm). For example, maximumupper distance 4192 can be 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch(7 mm), 0.31 inch (8 mm), 0.35 inch (8.89 mm), 0.39 inch (10 mm), 0.43inch (11 mm), 0.47 inch (12 mm), 0.51 inch (13 mm), 0.55 inch (14 mm),or 0.59 inch (15 mm). In some embodiments, maximum upper distance 4192can be 0.348 inch (9.09 mm). Further, a minimum upper distance 4194measured as the perpendicular distance from exterior surface 3703 ofstrikeface 3712 to the exterior surface 3703 of the back wall 3921 atthe first inflection point 3986 can range from 0.16 inch to 0.47 inch (4mm to 12 mm). For example, minimum upper distance 4194 can be 0.16 inch(4 mm), 0.20 inch (5 mm), 0.24 inch (6 mm), 0.28 inch (7 mm), 0.31 inch(8 mm), 0.35 inch (9 mm), 0.39 inch (10 mm), 0.43 inch (11 mm), or 0.47inch (12 mm). In some embodiments, minimum upper distance 4194 can be0.309 inch (7.85 mm). Further still, a maximum lower distance 4196measured as the perpendicular distance from exterior surface 3703 ofstrikeface 3712 to exterior surface 3703 of third reference point 3920of lower region 3713 can range from 0.670 inch to 0.98 inch (17 mm to 25mm). For example, maximum lower distance 4196 can be 0.670 inch (17 mm),0.709 inch (18 mm), 0.748 inch (19 mm), 0.787 inch (20 mm), 827 inch (21mm), 0.866 inch (22 mm), 0.906 inch (23 mm), 0.945 inch (24 mm), or 0.98inch (25 mm). In some embodiments, maximum lower distance 4196 can be0.863 inch (21.9 mm). In many embodiments, maximum lower distance 4196is greater than maximum upper distance 4192 and maximum upper distance4192 is greater than minimum upper distance 4194.

As illustrated in FIGS. 39-41, body 3701 is a hollow body club head thatfurther comprises internal cavity 3716. Internal cavity 3716 of the body3701 comprises a volume. The volume of the internal cavity 3716 canrange from 0.70 inch³ (11.47 cc) to 1.70 inches³ (27.86 cc). In someembodiments, the internal cavity 3716 can comprise a volume of be 0.70inch³ (11.47 cc), 0.80 inch³ (13.11 cc), 0.90 inch³ (14.75 cc), 1.00inch³ (16.39 cc), 1.10 inches³ (18.03 cc), 1.20 inches³ (19.66 cc), 1.30inches³ (21.30 cc), 1.40 inches³ (22.94 cc), or 1.50 inches³ (24.58 cc),1.60 inches³ (26.22 cc), or 1.70 inches³ (27.86 cc).

The internal cavity 3716 of the body 3701 further comprises interiorsurface 3919. In some embodiments, interior surface 3919 of rear 3710 isa planar and smooth surface. In other embodiments as illustrated in FIG.42, the interior surface 3919 of the internal cavity 3716 of rear 3710comprises a plurality of ribs 3952. The plurality of ribs 3952 extend ina direction from top rail 3715 toward sole 3706. Plurality of ribs 3952can be located anywhere on interior surface 3919 of rear 3710. In someexamples, plurality of ribs 3952 can be positioned onto a portion ofinterior surface 3919 of lower exterior wall 3927. In other examples,plurality of ribs 3952 can be position on a portion of interior surface3919 of rear wall 3923. In some embodiments, plurality of ribs 3952 canbe positioned on a portion of interior surface 3919 of rear 3710 and canextend into another portion of the rear 3710. For example, plurality ofribs 3952 are positioned on a portion of interior surface 3919 of rearwall 3923 and can extend up to at least a portion of the interiorsurface 3919 of top wall 3719, at least a portion of back wall 3921, orat least a portion of lower exterior wall 3927. The plurality of ribs3952 can comprise between 1 to 8 ribs. For example, the plurality ofribs 3952 can comprise one rib 3952, two ribs 3952, three ribs 3952,four ribs 3952, five ribs 3952, six ribs 3952, seven ribs 3952, or eightribs 3952. In embodiments having one or more plurality of ribs 3952, theplurality of ribs 3952 can be spaced equidistance from each other ormore concentrated near heel region 3702, toe region 3704, top rail 3715,or sole 3706. The plurality of ribs 3952 and the location of theplurality of ribs 3952 can help optimize the frequency and amplitude ofsound response.

In many embodiments, internal cavity 3716 of body 3701 can be void ofany substances. In other embodiments, internal cavity 3716 of body 3701can further comprise a polymer, wherein the polymer can at leastpartially fill the internal cavity 3716. The polymer can be polyethyleneterephthalate, high-density polyethylene, polyvinyl chloride,polycarbonate, polypropylene, other thermoplastics, composite polymersor any combination thereof. The polymer can fill 10% to 80% 10% to 25%,15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10% to 40%,30% to 60%, or 40% to 80% of the internal cavity 3716 of the body 3701.For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%, 40%,45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internal cavity3716 of the body 3701. In some embodiments, the polymer fills 80% of theinternal cavity 3716 of the body 3701.

The polymer comprises a specific gravity ranging from 0.5 to 4. Forexample, the specific gravity of the polymer can be 0.5, 1, 1.5, 2, 2.5,3, 3.5, or 4. In some embodiments, the specific gravity of the polymeris proportional to the mass of the polymer, wherein 1 specific gravityof the polymer is equal to 1 gram, 2 specific gravity of the polymer isequal to 2 grams and etc. Similarly, in some embodiments, the volume ofthe polymer is proportional to the polymer specific gravity. Forexample, the ratio of polymer mass to polymer volume can be 1 g to 1 cc,2 g to 2 cc, 3 g to 3 cc, or 4 g to 4 cc. However, in other embodiments,while the specific gravity of the polymer is proportional to the polymermass, the volume does not correlate to the specific gravity. Forexample, the ratio of polymer mass to polymer volume can be 1 g to 1 cc,2 g to 0 cc, 3 g to 1 cc, 4 g to 2 cc, 4 g to 3 cc, 3 g to 2 cc, 3 g to4 cc, or any other suitable ratio.

The mass of the polymer allows for the swing weight of the golf clubhead 3700 to be customizable for each player. Increasing the volume ofpolymer, and thus the mass, increases the swing weight, while decreasingthe volume of polymer decreases the swing weight. Having the appropriateswing weight for each individual player improves feel during a swing andcan improve performance such as swing speed, swing path and this ballspeed, and ball trajectory. The polymer can further increase the overallmass of the golf club head 3700 more toward the rear 3710 and sole 3706.Increasing the mass more toward the rear 3710 and sole 3706 can keep thecenter of gravity low and back, and there improve the moment of theinertia. The polymer can further still act as a dampener to improvesound, and absorb shock during impact.

The polymer volume when filled within the internal cavity 3716 can rangefrom 0 inch³ (0 cc) to 1.53 inches³ (25 cc), 0.244 inch³ (4 cc) to 1.22inches³ (20 cc), 0.305 inch³ (5 cc) to 0.915 inch³ (15 cc), 0.122 inch³(2 cc) to 0.488 inch³ (12 cc), or 0.854 inch³ (14 cc) to 1.34 inch³ (22cc). In some embodiments, the polymer volume inside the internal cavity3716 can be 0 inch³ (0 cc), 0.244 inch³ (4 cc), 0.244 inch³ (8 cc),0.488 inch³ (12 cc), 0.976 inch³ (16 cc), 1.22 inches³ (20 cc), or 1.53inches³ (25 cc). The polymer filled within the internal cavity 3716 cancover a percentage of the interior surface 3919 of the strikeface 3712ranging from 0% to 100%, 15% to 85%, 30% to 70%, 45% to 60%, 20% to 40%,or 60% to 80%. In some embodiments, the polymer covers 0%, 15%, 30%,45%, 60%, 75%, 90% or 100% of the interior surface 3919 of thestrikeface 3712. Increasing the percent coverage of the polymer on theinterior surface 3919 of the strikeface 3712 increases the support forthe strikeface 3712, thereby allowing for a thinner strikeface 3712.Thinning the strikeface 3712 can increase the deflection of thestrikeface 3712 upon impact with a ball which can impart the ball withincreases speed and spin. Thinning the strikeface 3716 also allows forweight to be redistributed elsewhere on the body 3701 to optimize centerof gravity and moment of inertia.

In some embodiments as illustrated in FIG. 43, the golf club head 3700can further comprise a first aperture 3934 located on toe region 3704and a second aperture 3936 located in a hosel of the golf club head3700. The first aperture 3924 is configured to receive a toe weight (notpictured), wherein the toe weight can range from 2 grams to 7 grams. Insome embodiments, the toe weight can be 2 grams, 3 grams, 4 grams, 5grams, 6 grams, or 7 grams. The second aperture 3936 is configured toreceive a tip weight (not pictured), wherein the tip weight can rangefrom 2 grams to 7 grams. In some embodiments, the tip weight can be 2grams, 3 grams, 4 grams, 5 grams, 6 grams, or 7 grams. In manyembodiments, the first aperture 3934 and the second aperture 3936 canfurther be configured to receive the polymer. The first aperture 3934can receive 1 gram to 9 grams of polymer (e.g., 1 gram, 2 grams, 3grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams, or 9 grams).Similarly, the second aperture 3936 can receive 1 gram to 9 grams ofpolymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7grams, 8 grams, or 9 grams). The toe and tip weight, and the polymerhoused within the first aperture 3934 and the second aperture 3936 canaffect the swing weight to optimize CG and MOI.

In many embodiments, cavity 3730 can provide an increase in golf ballspeed over golf club head 1200, or other standard golf club heads, canreduce the spin rate of standard hybrids club heads, and can increasethe launch angle over both the standard hybrid and iron club heads. Inmany embodiments, the shape of cavity 3730 determines the level ofspring and timing of the response of golf club head 3200. When the golfclub ball impacts strikeface 3712 of club head 3700 with cavity 3730,strikeface 3712 springs back like a drum, and a rear 3710 bends in acontrolled buckle manner. In many embodiments, top rail 3715 can absorbmore stress over greater volumetric space than a top rail in a golf clubhead without cavity 3730. The length, depth and width of cavity 3730 canvary. These parameter provide control regarding how much spring back ispresent in the overall design of club head 3700.

Upon impact with the golf ball, strikeface 3712 can bend inward at agreater distance than on a golf club without cavity 3730. In someembodiments, strikeface 3712 has a 10% to a 50% greater deflection thana strikeface on a golf club head without cavity 3730. In someembodiments, strikeface 3712 has a 5% to 40% or a 10% to a 20% greaterdeflection than a strikeface on a golf club head without cavity 3730.For example, strikeface 3712 can have a 5%, 10%, 15%, 20%, 25%, 30%,35%, or 40% greater deflection than a strikeface on a golf club headwithout cavity 3730. In many embodiments, there is both a greaterdistance of retraction by strikeface 3712 due to the hinge and bendingof cavity 3730 over a standard strikeface that does not have a backportion of the club with the cavity.

In many embodiments, the face deflection is greater with club head 3700having cavity 3730, as a greater buckling occurs at first inflectionangle 3986 of top wall 3219 upon impact with a golf ball. Cavity 3730,however, provides a greater dispersion of stress along top rail 3715,rear wall 3923, and top wall 3719, and the spring back force istransferred from cavity 3730 and first inflection point 3986 of top wall3719 to strikeface 3712. A standard top rail, rear wall and top wallwithout a cavity does not have this hinge/buckling effect, nor does itabsorb a high level of stress over a large volumetric area of the toprail, rear wall and top wall. Therefore, the standard strikeface doesnot contract and then recoil as much as strikeface 3712. Further, both alarger region of srikeface 3712, top rail 3715, rear wall 3923, and topwall 3719 absorb more stress than the same crown region of a standardgolf club head with a standard top rail, top wall and no cavity. In manyembodiments, although there is greater stress along a greater area abovecavity 3730 that the same area in a standard club without the cavity,the durability of the club head with and without the cavity is the same.By adding more spring to the back end of the club (due to inwardinclination of a portion of top wall 3719 toward strikeface 3712), moreforce is displace throughout the volume of the structure. The stress isobserved over a greater area of strikeface 3712, top rail 3715, rearwall 3923, and top wall 3719 of golf club head 3700. Peak stresses canbe seen in the standard top rail club head. However, more peak stressesare seen in golf club head 3700, but distributed over a large volume ofthe material. The hinge and bend regions of golf club head 3700 (i.e.,the region above cavity 3730 and cavity 3730 itself) will not deform aslong as the stress does not meet the critical buckling threshold. Cavity3730 and its placement can be designed to be under the critical K valueof the buckling threshold.

As shown in FIG. 41, a further deflection feature of the golf club head3700 can be the uniform thinned region 4160, located at the sole 3706and stretching between the rear 3710 of the body 3701 and the strikeface3712, toward a cascading sole portion of the sole (as described ingreater detail below). The uniform thinned region 4160 can providemultiple benefits. First, the uniform thinned region 4160 can reducestress on the strikeface 3712 caused during impact with the golf ball.Second, the uniform thinned region 4160 can bend allowing the strikeface3712 to experience greater deflection. Third, the uniform thinned region4160 removes weight from the sole area, allowing the weight to beredistributed more toward the rear of the golf club head 3700. Atimpact, the energy imparted to the strikeface 3712 by the golf ball cancause the uniform thinned region to bend outward, which in turnincreases the strikeface 3712 deflection. After bending, the uniformthinned region 4160 rebounds back to its original position returning themajority of the energy from impact back to the golf ball. The result isthe golf club head 3700 imparts increased ball speeds and greater traveldistances to the golf ball after impact.

In some embodiments, body 3701 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 3701can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 3712 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 3712 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 3701 can comprise the same material as strikeface3712. In some embodiments, body 3701 can comprise a different materialthan strikeface 3712.

FIG. 44 illustrates a back perspective view of an embodiment of golfclub head 4400 and FIG. 45 illustrates a back heel-side perspective viewof golf club head 4400 according to the embodiment of FIG. 44. In someembodiments, golf club head 4400 can be similar to golf club head 1000(FIG. 10), golf club head 2200 (FIG. 22), golf club head 2700 (FIG. 27),golf club head 3200 (FIG. 32), and/or golf club head 3700 (FIG. 37).Golf club head 4400 can be an iron-type golf club head. In otherembodiments, golf club head 4400 can be a hybrid-type, or a fairwaywood-type golf club head. In some embodiments, golf club head 4400 doesnot comprise a badge or a custom tuning port.

Golf club head 4400 comprises a body 4401. In some embodiments, body4401 can be similar to body 1001 (FIG. 10), body 2201 (FIG. 22), body2701 (FIG. 27), body 3201 (FIG. 32), and/or body 3701 (FIG. 37). Body4401 further comprises an exterior surface 4403, a strikeface 4412, aheel region 4402, a toe region 4404 opposite the heel region 4402, asole 4406, a top rail 4415, and a rear 4410.

Body 4401 of FIGS. 44-48 further comprises a blade length. The bladelength for body 4401 can be measured similar to blade length 3725 asshown and described in FIG. 43 (i.e., a measurement parallel to the flatsurface of the strikeface 3712, from a toe edge 3726 of the strikeface3712, to strikeface end 3727 before the strikeface 3712 integrallycurves into the hosel). The blade length of the body 4401 can range from2.50 inches (6.35 cm) to 2.90 inches (7.37 cm). For example, in someembodiments, the body 3701 can comprise a blade length of 2.50 inch(6.35 cm), 2.54 inch (6.45 cm), 2.58 inch (6.55 cm), 2.62 inch (6.65cm), 2.66 inch (6.76 cm), 2.70 inch (6.86 cm), 2.74 inch (6.96 cm), 2.78inch (7.06 cm), 2.82 inch (7.16 cm), 2.86 inch (7.264 cm), or 2.90 inch(7.37 cm).

As shown in FIG. 48, a further deflection feature of the golf club head4400 can be the uniform thinned region 4860, located at the sole 4406and stretching between the rear 4410 of the body 4401 and the strikeface4412, toward a cascading sole portion of the sole (as described ingreater detail below). In the illustrated embodiment, the uniformthinned region 4860 comprises a sole thickness measured perpendicularfrom the exterior surface 4403 to an interior surface 4619 at theuniform thinned region 4860, which can remain constant from the bottomof the strikeface 4412 to adjacent the cascading sole portion of thesole. In some embodiments, the sole thickness of the uniform thinnedregion 4860 can be thinner than a conventional sole. For example, insome embodiments, the sole thickness of the uniform thinned region 4860may range from approximately 0.040 inch to 0.080 inch. In otherembodiments, the sole thickness of the uniform thinned region 4860 maybe within the range of 0.040 inch to 0.050 inch, 0.050 inch to 0.060inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080 inch, 0.040 inch to0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to 0.065 inch, 0.055inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065 inch to 0.080inch. For example, the sole thickness of the uniformed thinned region4860 can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060 inch, 0.065 inch,0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 46 illustrates a cross-section of golf club head 4400 along thecross-sectional line XLVI-XLVI in FIG. 44, according to one embodiment.As seen in FIG. 46, strikeface 4412 comprises a high region 4676, amiddle region 4674, and a low region 4672.

The strikeface 4412 of the body 4401 further comprises a thickness 4654measured perpendicularly to the strikeface 4412 from the exteriorsurface 4403 to an interior surface 4619. The thickness 4654 of thestrikeface 4412 can range from 0.040 inch to 0.100 inch. For example,the thickness 4654 of the strikeface 4412 can be 0.040 inch, 0.045 inch,0.050 inch, 0.055 inch, 0.060 inch, 0.065 inch, 0.070 inch, 0.075 inch,0.080 inch, 0.085 inch, 0.090 inch, 0.095 inch, or 0.100 inch. In someembodiments, thickness 4654 of the strikeface 4412 can vary from theheel region 4402 to the toe region 4404, and/or from the top rail 4415to the sole 4406. For example, the thickness 4654 of the strikeface 4412can be greatest at the central portion near the middle region 4674 ofthe strikeface 4412, and taper along the periphery near the high region4676 and the low region 4672 of strikeface 4412. In many embodiments,the center of the strikeface 4412 can have a thickness 4654 of 0.090inch and the periphery of the strikeface 4412 can have a thickness 4654of 0.070 inch. In other examples, the thickness 4654 can increase,decrease, or any variation thereof starting at the central region nearthe middle region 4674 of the strikeface 4412 and extending toward theperiphery near the high region 4676 and the low region 4672.

The cross-section of golf club head 4400 in FIG. 46 further illustratesthe rear 4410. The rear 4410 can comprise an upper region 4411, a lowerregion 4413, and an inflection point 4686 disposed between the upperregion 4411 and the lower region 4413. The inflection point 4686 isfurther located at the junction between the rear wall 4623 and thebottom incline 4625. The inflection point 4686 is located nearer to thesole of the club head than the top rail 4415.

The upper region 4411 of rear 4410 comprises a top rail 4415, an apex4628 of top rail, a rear wall 4623 orientated parallel to the strikeface4412, and a first reference point 4622 disposed between the top rail4415 and the rear wall 4623. The first reference point 4622 is locatedat the junction between the top rail 4415 and the rear wall 2623parallel to the strikeface 4412. In many embodiments, the rear wall 4623of upper region 4411 is located below and adjacent the top rail 4415.

In some embodiments, top rail 4415 of the upper region 4411 can be aflatter and taller top rail or skirt than in irons known to one skilledin the art. The flatter and taller rail can compensate for mishits orstrikeface 4412 to increase playability off the tee. In someembodiments. The length of top rail 4415, measured from heel region 4402to toe region 4404, can be 70% to 95% of the length of the golf clubhead 4400.

The top rail 4415 of the upper region 4411 comprises a thickness 4652.The thickness 4652 of the top rail 4415 can range from 0.040 inch to0.080 inch. For example, the thickness 4652 of the top rail 4415 can be0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.051 inch, 0.054 inch,0.057 inch, 0.060 inch, 0.063 inch, 0.066 inch, 0.069 inch, 0.071 inch,0.074 inch, 0.077 inch, or 0.080 inch. In many embodiments, thethickness 4652 of the top rail 4415 is constant throughout. In otherembodiments, the thickness 4652 of the top rail 4415 can vary. In theexemplary embodiment, the thickness 4652 of the top rail 4415 decreasesfrom the strikeface 4412 toward the rear wall 4623. In many embodimentsdue to the thickness 4652 of the top rail, top rail 4415 can provide anincrease in the overall bending of strikeface 4412. In some embodiments,the bending of strikeface 4412 can allow for a 2% to 5% increase ofenergy.

FIG. 47 illustrated the top rail 4415 and a portion of the rear 4410 ofthe cross-section of the golf club head 4400 of FIG. 46, different fromcross-section of golf club head 1200 as shown in FIG. 13. The strikeface 4412 further comprises a strikeface angle 4750. Strikeface angle4750 is measured from the strikeface 4412 to the top rail 4415, whereinthe strikeface angle 4750 can range from 70 degrees to 160 degrees or 70degrees to 110 degrees. In some embodiments, strikeface angle 4050 canbe 70 degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, 150degrees, 155 degrees, or 160 degrees.

FIG. 47 further illustrates the top rail 4415 comprising a top railangle 4745. The top rail angle 4745 is measured from rear wall 4623 tothe top rail 4415. In many embodiments, the top rail angle 4745 canrange from 35 degrees to 120 degrees or 70 degrees to 110 degrees. Insome embodiments, top rail angle 4745 can be 35 degrees, 40 degrees, 45degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, or 120 degrees.

The rear wall 4623 of the upper region 4411 comprises a height 4680. Theheight 4680 of the rear wall 4623 is measured from the first referencepoint 4622 to the inflection point 4686, wherein the first referencepoint 4622 is positioned at the junction between the top rail 4415 andthe rear wall 4623 parallel to the strikeface 4412. The height 4680 ofthe rear wall 4623 can range from 0.055 inch to 0.060 inch, 0.060 inchto 0.070 inch, 0.070 inch to 0.080 inch, 0.080 in to 0.085 or 0.55 inchto 0.85 inch. For example, the height 4680 of the rear wall 4623 can be0.55 inch, 0.58 inch, 0.61 inch, 0.64 inch, 0.67 inch, 0.70 inch, 0.73inch, 0.76 inch, 0.79 inch, 0.82 inch, or 0.85 inch. In someembodiments, the height 4680 of the rear wall 4623 range from 35% to60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to 40%, 35% to 45%, 40% to50%, 45% to 55%, or 50% to 60% of the total height of the golf club head4400. For example, the height 4680 of the rear wall 4623 can be 35%,38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% of the total height of thegolf club head 4400.

The rear wall 4623 of the upper region 4411 can also comprise a height4680A. The height 4680A is measured from the apex 4628 of the top rail4415 to the inflection point 4686. The height 4680A can range from 0.60inch to 1.0 inch. For example, the height 4680A can be 0.60 inch, 0.61inch, 0.64 inch, 0.67 inch, 0.70 inch, 0.73 inch, 0.76 inch, 0.79 inch,0.82 inch, 0.85 inch, 0.90 inch, 0.95 inch, or 1.0 inch. In someembodiments, the height 4680A can range from 40% to 75% of the totalheight of the golf club head 4400. For example, the height 4680A can be40%, 44%, 47%, 50%, 53%, 56%, 60%, 65%, 70%, or 75% of the total heightof the golf club head 4400.

The rear wall 4623 of the upper region 4411 further comprises athickness 4656. The thickness 4656 is the perpendicular distance of therear wall 4623 from the outer surface 4403 to the inner surface 4619.The thickness 4656 of the rear wall 4623 can range from 0.040 inch to0.080 inch. For example, the thickness 4656 of the rear wall 4623 can be0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.051 inch, 0.054 inch,0.057 inch, 0.060 inch, 0.063 inch, 0.066 inch, 0.069 inch, 0.071 inch,0.074 inch, 0.077 inch, or 0.080 inch. In many embodiments, thethickness 4656 of the rear wall 4623 is constant throughout. In otherembodiments, the thickness 4656 of the rear wall 4623 can vary. In theexemplary embodiment, the thickness 4656 of the rear wall 4623 is aconstant 0.05 inch. The thickness 4656 of the rear wall 4623 allowsenergy from an impact to transfer to the inflection point 4686 to helpinduce a buckling effect.

The lower region 4413 of the body 4401 comprises a bottom incline 4625,a lower exterior wall 4627, a second reference point 4682, and a thirdreference point 4620. The bottom incline 4625 is below and adjacent theinflection point 4686. The lower exterior wall 4627 is below andadjacent the bottom incline 4625. The second reference point 4682 isdisposed between or positioned at the junction between the bottomincline 4625 and the lower exterior wall 4627. The third reference point4620 is disposed between the lower exterior wall 4727 and the sole 4406.The bottom incline 4625 is angled away from the top rail 4415 and awayfrom the strikeface 4412 in a direction toward the second referencepoint 4682.

In some embodiments, bottom incline 4625 of the lower region 4413comprises a bottom incline length 4629. Bottom incline length 4629 ismeasured from the inflection point 4686 to the second reference point4682. The bottom incline length 4629 can range from 0 inch to 0.45 inch.For example, the bottom incline length 4629 can be 0 inch, 0.05 inch,0.10 inch, 0.15 inch, 0.20 inch, 0.20 inch, 0.25 inch, 0.30 inch, 0.35inch, 0.40 inch, or 0.45 inch. In some embodiments, the bottom inclinelength 4629 can remain constant from the heel region 4402 to the toeregion 4404. In other embodiments, the bottom incline length 4629 canvary from the heel region 4402 to the toe region 4404. For example, thebottom incline length 4629 can increase from the heel region 4402 to thetoe region 4404 as illustrated in FIG. 44. In other embodiments, thebottom incline length 4629 can decrease from the heel region 4402 to thetoe region 4404.

In some embodiments, the lower region 4413 further comprises a lowerangle 4651 measured from between the bottom incline 4625 to the lowerexterior wall 4627. In some embodiments, the lower angle 4651 can beless than 180 degrees. In a number of embodiments, the lower angle 4651can be 130 degrees to 175 degrees. For example, the lower angle 4651 ofthe lower region 4413 can be 130 degrees, 135 degrees, 140 degrees, 145degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170degrees, or 175 degrees.

The upper region 4411 and the lower region 4413 of the rear 4410 isseparated by the inflection point 4686. Due to the height 4680 of therear wall 4623, the inflection point 4686 is positioned low on the body4401. In many embodiments, the inflection point 4686 is positioned atleast 40% down on the body 4401 below the apex 4628. For example, theinflection point 4686 can be positioned 40%, 42%, 44%, 46%, 48%, 50%,52%, 54%, 56%, 58%, or 60% down on the body 4401 below the apex 4628.The low positioned inflection point 4686 allows for more leverage on theupper region 4411 to experience increased bending during impact with aball, compared to a similar golf club head having a higher inflectionpoint position.

The inflection point 4686 comprises an inflection angle 4696 measuredfrom the rear wall 4623 of the upper region 4411, to the bottom incline4625 of the lower region 4413. In some embodiments, the inflection angle4696 can be measured from the rear wall 4623 to the lower exterior wall4627 in the absence of the bottom incline 4625 (i.e., the bottom inclinelength 4629 is 0 inch). The inflection angle 4696 of the inflectionpoint 4686 can range from at least 95 degrees to 150 degrees. In someembodiments, the inflection angle 4696 can be at least 95 degrees, 100degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150degrees. In some embodiments, the inflection angle 4696 can beconsistent from the heel region 4402 to the toe region 4404. In otherembodiments, the inflection angle 4696 can vary from the heel region4402 to the toe region 4404. In many embodiments, the inflection angle4696 allows for inflection point 4686 to act as a buckling point orplastic hinge upon the golf club head 4400 impacting the golf ball atstrikeface 4412. In other examples of a similar golf club head having aninflection angle, wherein the inflection angle is less than 95 degrees(i.e., 90 degrees, or the bottom incline is oriented approximatelyperpendicular to the strikeface), the inflection angle would impedeenergy transfer and prevent bending at the inflection point.

The inflection point 4686 further comprises a thickness 4660. Thethickness 4660 of the inflection point 4686 is measured perpendicularlyof the inflection point 4686 from the exterior surface 4403 to theinterior surface 4619. The thickness 4660 of the inflection point 4686can range from 0.040 inch, to 0.080 inch. For example, the thickness4660 can be 0.040 inch, 0.045 inch, 0.050 inch, 0.055 inch, 0.060 inch,0.65 inch, 0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch. In manyembodiments, the thickness 4660 at the inflection point 4686 is constantwith the thickness 4656 of the rear wall 4623 and the thickness 4658 ofthe bottom incline 4625. In other embodiments, the thickness 4660 at theinflection point 4686 can be less than the thickness 4656 of the rearwall 4623 and the thickness 4658 of the bottom incline 4656. Thethickness 4660 at the inflection point 4686 being consistent with orless than the thickness 4656, 4658 of the rear wall 4623 and the bottomincline 4656 allows for more uniform energy transfer and bending.

FIG. 48 illustrates another cross-sectional view of the golf club head4400, similar to the detailed cross-section of golf club head 4400illustrated in FIG. 44. The body 4401 of golf club head 4400 furthercomprises a minimum distance 4616, and a maximum distance 4618. Theminimum distance of the body 4401 is measured as the perpendiculardistance from the exterior surface 4403 of the strikeface 4412 in theupper region 4411 to the exterior surface 4403 of the rear wall 4623.The minimum distance 4616 can range from 0.20 inch to 0.40 inch. Forexample, the minimum distance 4616 can be 0.20 inch, 0.22 inch, 0.24inch, 0.26 inch, 0.28 inch, 0.30 inch, 0.32 inch, 0.34 inch, 0.36 inch,0.038 inch, or 0.40 inch. In some embodiments, the minimum distance 4616of the body 4401 can be less the bottom incline length 4629. The maximumdistance 4618 of the body 4401 is measured as the perpendicular distancefrom the exterior surface 4403 of the strikeface 4412 in the lowerregion 4413 to the exterior surface 4403 of the third reference point4620. The maximum distance 4618 can range from 0.60 inch to 0.90 inch.For example, the maximum distance 4618 can be 0.60 inch, 0.64 inch, 0.68inch, 0.72 inch, 0.76 inch, 0.80 inch, 0.84 inch, 0.88 inch, or 0.90inch.

As illustrated in FIG. 46-48, the golf club head 4400 can be a hollow,or at least partially hollow body comprising an internal cavity 4416.Internal cavity 4416 of the body 4401 comprises a volume. The volume ofthe internal cavity 4416 can range from 0.65 inch³ (10.65 cm³) to 1.05inch³ (17.21 cm³). In some embodiments, the internal cavity 4416 cancomprise a volume of 0.65 inch³ (10.65 cm³), 0.70 inch³ (11.47 cm³),0.75 inch³ (12.29 cm³), 0.80 inch³ (13.11 cm³), 0.85 inch³ (13.93 cm³),0.90 inch³ (14.75 cm³), 0.95 inch³ (15.57 cm³), 1.00 inch³ (16.39 cm³),or 1.05 inch³ (17.21 cm³). Similarly, the solid portion of the body4401, void of the cavity 4416, further comprises a material volume. Thematerial volume of the body 4401 can range from 2.50 inch³ (40.97 cm³)to 3.50 inch³ (57.35 cm³). For example, the material volume of the body4401 can be 2.50 inch³ (40.97 cm³), 2.60 inch³ (42.61 cm³), 2.70 inch³(44.25 cm³), 2.80 inch³ (45.88 cm³), 2.90 inch³ (47.52 cm³), 3.00 inch³(49.16 cm³), 3.10 inch³ (50.80 cm³), 3.20 inch³ (52.44 cm³), 3.30 inch³(54.08 cm³), 3.40 inch³ (55.72 cm³), or 3.50 inch³ (57.35 cm³).

In many embodiments, the internal cavity 4416 of the body 4401 can bevoid of any substance. In other embodiments, the internal cavity 4416 ofthe body 4401 can comprise a polymer (not pictured), wherein the polymercan be at least partially fill the internal cavity 4416. The polymer canbe polyethylene terephthalate, high-density polyethylene, polyvinylchloride, polycarbonate, polypropylene, other thermoplastics, compositespolymers or any combination thereof. The polymer can fill 10% to 80% 10%to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10%to 40%, 30% to 60%, or 40% to 80% of the internal cavity 4416 of thebody 4401. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internalcavity 4416 of the body 4401. In some embodiments, the polymer fills 80%of the internal cavity 4416 of the body 4401.

The polymer to at least partially fill the internal cavity 4416 of thebody 4401 comprises a specific gravity ranging from 0.05 to 4. Forexample, the specific gravity of the polymer can be 0.5, 1.0, 1.5, 2.0,2.5, 3.0, 3.5, or 4. In some embodiments, the specific gravity of thepolymer is proportional to the mass of the polymer, wherein 1 specificgravity of the polymer is equal to 1 gram. Similarly, in those exemplaryembodiments, the volume is proportional to the polymer specific gravity,wherein 1 specific gravity of the polymer is equal to 1 cc. In otherembodiments, the volume is not proportional to the specific gravity ofthe polymer. For example, the ratio of the polymer specific gravity tothe polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4cc, 4:1 cc, 4:2 cc, or 4:3 cc.

The mass of the polymer allows for the swing weight of the golf clubhead 4400 to be customizable for each player. Increasing the volume ofthe polymer, and thus the mass, increases the swing weight. Similarly,decreasing the volume of the polymer decreases the swing weight. Havingthe appropriate swing weight for each individual player improves feelduring a swing and can improve performance such as swing speed, swingpath, ball speed, and ball trajectory. The polymer can further increasethe overall mass of the golf club head 4400 more toward the sole 4406.Increasing the mass more toward the sole shifts the CG low and back,thereby improves the moment of inertia.

In some embodiments, the golf club head 4400 can further comprise anaperture (not pictured) located on the toe region 4404. The aperturecomprises internal threads and is configured to receive a threaded screwweight (not pictured). The threaded screw weight comprises a mass,wherein the mass of the threaded screw weight can range from 2 grams to12 grams. In other embodiments, the mass of the threaded screw weightcan range from 4 grams to 10 grams. In some embodiments, the screwweight can be 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8grams, 9 grams, 10 grams, 11 grams, or 12 grams. The mass of the screwweight correlates with the length of the screw weight, wherein a longerthreaded screw weight equates to a greater mass. The threaded screwweight further affects the mass and overall swing weight of the golfclub head 4400. Therefore, the threaded screw weight can improve thefeel of the golf club head 4400, as well as performance characteristics(e.g., swing speed, ball speed, and ball flight).

In many embodiments, the low positioning of the inflection point 4686can provide an increase in golf ball speed over golf club head 1200 (orother standard golf club heads), can reduce the spin rate of standardhybrid club heads (or other standard golf club heads), and can increasethe launch angle over both the standard hybrid and iron club heads. Aninflection point positioned less than 40% down the body from the apexcannot buckle as easily because the high positioning decreases theleverage for the upper region to bend. Therefore, when the golf ballimpacts strikeface 4412 of the club head 4400 with inflection point 4686positioned at least 40% down the body 4401 from the apex 4628, thestrikeface 4412 springs back like a drum, and the rear 4410 bends in acontrolled buckle manner more than a golf club head having an inflectionpoint positioned less than 40% down the body from the apex.

A standard top rail, and rear wall without a low positioned inflectionpoint does not have this hinge/buckling effect, nor does it absorb ahigh level of stress over a large volumetric area of the top rail andrear wall. Therefore, the standard strikeface does not contract and thenrecoil as much as strikeface 4412. By adding more spring to the back endof the club (due to the thinness of the top rail 4415 and rear wall4623, and the low position of the inflection point 4686), more force isdisplaced throughout the volume of the structure. The stress is observedover a greater area of strikeface 4412, top rail 4415, and rear wall4623 of the golf club head 4400. Peak stresses can be seen in thetypically just along the top rail in a standard club head. However, morepeak stresses are seen in the golf club head 4400, but distributed overa large volume of the material. The hinge and bend regions of the golfclub head 4400 (i.e., the inflection point 4686) will not deform as longas the stress does not meet the critical buckling threshold. Inflectionpoint 4686 and its placement can be designed to be under the critical Kvalue of the buckling threshold.

Further, upon impact with the golf ball, strikeface 4412 can bend inwardat a greater distance than on a golf club without a thin top rail 4415,a thin rear wall 4623, and an inflection point 4686 positioned at least40% down the body from the apex 4628. In some embodiments, thestrikeface 4412 has a 10% to a 50% greater deflection than a strikefaceon a golf club head without a thin top rail, a thin rear wall, and a lowpositioned inflection point. For example, the strikeface 4412 can have a10%, a 15%, a 20%, a 30%, a 35%, a 40%, a 45%, or a 50% greaterdeflection than a strikeface of a golf club head without a thin top rail4415, thin rear wall 4623, and low positioned inflection point 4686.

As shown in FIG. 48, a further deflection feature of the golf club head4400 can be the uniform thinned region 4860, located at the sole 4406and stretching between the rear 4410 of the body 4401 and the strikeface4412, toward a cascading sole portion of the sole (as described ingreater detail below). The uniform thinned region 4860 can providemultiple benefits. First, the uniform thinned region 4860 can reducestress on the strikeface 4412 caused during impact with the golf ball.Second, the uniform thinned region 4860 can bend allowing the strikeface4412 to experience greater deflection. Third, the uniform thinned region4860 removes weight from the sole area, allowing the weight to beredistributed more toward the rear of the golf club head 4400. Atimpact, the energy imparted to the strikeface 4412 by the golf ball cancause the uniform thinned region 4860 to bend outward, which in turnincreases the strikeface 4412 deflection. After bending, the uniformthinned region 4860 rebounds back to its original position returning themajority of the energy from impact back to the golf ball. The result isthe golf club head 4400 imparts increased ball speeds and greater traveldistances to the golf ball after impact.

In some embodiments, body 4401 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 4401can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 4412 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 4412 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 4401 can comprise the same material as strikeface4412. In some embodiments, body 4401 can comprise a different materialthan strikeface 4412.

FIG. 49 illustrates a back perspective view of an embodiment of a golfclub head 4900, and FIG. 50 illustrates a back heel-side perspectiveview of the golf club head 4900 according to the embodiment of FIG. 49.In some embodiments, the golf club head 4900 can be similar to golf clubhead 1000 (FIG. 10), golf club head 2200 (FIG. 22), golf club head 2700(FIG. 27), golf club head 3200 (FIG. 32), golf club head 3700 (FIG. 37),and/or golf club head 4400 (FIG. 44). The golf club head 4900 can be aniron-type golf club head. In some embodiments, the golf club head 4900does not comprise a badge or a custom tuning port.

The golf club head 4900 comprises a body 4901. In some embodiments, thebody 4901 can be similar to body 1001 (FIG. 10), body 2201 (FIG. 22),body 2701 (FIG. 27), body 3201 (FIG. 32), body 3701 (FIG. 37), and/orbody 4401 (FIG. 44). The body 4901 further comprises an exterior surface4903, a strikeface 4912, a heel region 4902, a toe region 4904 oppositethe heel region, a sole 4906, a top rail 4915, and a rear 4910.

The body 4901 of FIGS. 49-52 further comprises a blade length. The bladelength for the body 4901 can be measured similar to blade length 3725 asshown and described for golf club head 3700 in FIG. 43 (i.e., ameasurement parallel to the flat surface of the strikeface, from a toeedge of the strikeface, to strikeface end before the strikefaceintegrally curves into the hosel). The blade length of the body 4901 canrange from 2.50 inches (6.35 cm) to 2.90 inches (7.37 cm). In someembodiments, the blade length can range from 2.50 inches (6.35 cm) to2.60 inches (6.60 cm), 2.60 inches (6.60 cm) to 2.70 inches (6.86inches), 2.70 inches (6.86 cm) to 2.80 inches (7.11 cm), or 2.80 inches(7.11 cm) to 2.90 inches (7.37 cm). For example, in some embodiments,the body 4901 can comprise a blade length of 2.50 inches (6.35 cm), 2.54inches (6.45 cm), 2.58 inches (6.55 cm), 2.62 inches (6.65 cm), 2.66inches (6.76 cm), 2.70 inches (6.86 cm), 2.74 inches (6.96 cm), 2.78inches (7.06 cm), 2.82 inches (7.16 cm), 2.86 inches (7.264 cm), or 2.90inches (7.37 cm).

As shown in FIG. 53, a further deflection feature of the golf club head4900 can be the uniform thinned region 5360, located at the sole 4906and stretching between the rear 4910 of the body 4901 and the strikeface4912, toward a cascading sole portion of the sole (as described ingreater detail below). In the illustrated embodiment, the uniformthinned region 5360 comprises a sole thickness 5361 measuredperpendicular from the exterior surface 4903 to an interior surface 5119at the uniform thinned region 5360, which can remain constant from thebottom of the strikeface 4912 to adjacent the cascading sole portion ofthe sole 4906. In some embodiments, the sole thickness 5361 of theuniform thinned region 5360 can be thinner than a conventional sole. Forexample, in some embodiments, the sole thickness 5361 of the uniformthinned region 5360 may range from approximately 0.040 inch to 0.080inch. In other embodiments, the sole thickness 5361 of the uniformthinned region 5360 may be within the range of 0.040 inch to 0.050 inch,0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070 inch to 0.080inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch, 0.050 inch to0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075 inch, or 0.065inch to 0.080 inch. For example, the sole thickness of the uniformedthinned region 5360 can be 0.040 inch, 0.045 inch, 0.050 inch, 0.060inch, 0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 51 illustrates a cross-section of the golf club head 4900,according to one embodiment. As seen in FIG. 51, the strikeface 4912comprises a high region 5176, a middle region 5174, and a low region5172.

The strikeface 4912 of the body 4901 further comprises a thickness 5154measured perpendicular to the strikeface 4912 from the exterior surface4903 to an interior surface 5119. The thickness 5154 of the strikeface4912 can range from 0.040 inch to 0.200 inch. In some embodiments, thethickness 5154 of the strikeface 4912 can range from 0.040 inch to 0.080inch, 0.080 inch to 0.120 inch, 0.120 inch to 0.160 inch, or 0.160 inchto 0.20 inch. For example, the thickness 5154 of the strikeface 4912 canbe 0.040 inch, 0.045 inch, 0.050 inch, 0.055 inch, 0.060 inch, 0.065inch, 0.070 inch, 0.075 inch, 0.080 inch, 0.085 inch, 0.090 inch, 0.095inch, 0.100 inch, 0.150 inch, or 0.200 inch. In some embodiments, thethickness 5154 of the strikeface 4912 can vary from the heel region 4902to the toe region 4904, and/or from the top rail 4915 to the sole 4906.For example, the thickness 5154 of the strikeface 4912 can be greatestat the central portion near the middle region 5174 of the strikeface4912, and taper along the periphery near the high region 5176 and thelow region 5172 of strikeface 4912. In many embodiments, the center ofthe strikeface 4912 can have a thickness 5154 range of 0.10 inch to 0.14inch, and the periphery of the strikeface 4912 can have a thickness 5154range of 0.06 inch to 0.10 inch. In some embodiments, the center of thestrikeface 4912 can have a thickness 5154 range of 0.10 inch to 0.12inch, or 0.12 inch to 0.14 inch. In other embodiments, the periphery ofthe strikeface 4912 can have a thickness 5154 range of 0.06 inch to 0.08inch, or 0.08 inch to 0.10 inch. In other examples, the thickness 5154can increase, decrease, or any variation thereof starting at the centralregion near the middle region of the strikeface and extending toward theperiphery near the high region 5176 and the low region 5172.

The cross-section of the golf club head in FIG. 51 further illustratesthe rear 4910. The rear 4910 can comprise an upper region 4911, a lowerregion 4913, and an inflection point 5186 disposed between the upperregion 4911 and the lower region 4913. The inflection point 5186 isfurther located at the junction between the rear wall 5123 and thebottom incline 5125. The inflection point 5186 is located nearer to thesole 4906 of the club head 4900 than the top rail 4915.

The upper region 4911 of rear 4910 comprises a top rail 4915, an apex oftop rail 5128, a rear wall 5123 orientated parallel to the strikeface4912, and a first reference point 5122 disposed between the top rail4915 and the rear wall 5123. The first reference point 5122 is locatedat the junction between the top rail 4915 and the rear wall 5123parallel to the strikeface. In many embodiments, the rear wall 5123 ofthe upper region 4911 is located below and adjacent the top rail 4915.

In some embodiments, top rail 4915 of the upper region 4911 can be aflatter and taller top rail or skirt than in irons known to one skilledin the art. The flatter and taller rail can compensate for mishits orstrikeface 4912 to increase playability off the tee. In someembodiments. The length of top rail 4915, measured from heel region 4902to toe region 4904, can be 60% to 95% of the length of the golf clubhead 4900.

The top rail 4915 of the upper region 4911 comprises a thickness 5152.The thickness 5152 of the top rail 4915 can range from 0.040 inch to0.080 inch. In some embodiments, the thickness 5152 of the top rail 4915can range from 0.040 inch to 0.060 inch, or 0.060 inch to 0.080 inch.For example, the thickness 5152 of the top rail 4915 can be 0.040 inch,0.043 inch, 0.046 inch, 0.049 inch, 0.051 inch, 0.054 inch, 0.057 inch,0.060 inch, 0.063 inch, 0.066 inch, 0.069 inch, 0.071 inch, 0.074 inch,0.077 inch, or 0.080 inch. In many embodiments, the thickness 5152 ofthe top rail 4915 is constant throughout. In other embodiments, thethickness 5152 of the top rail 4915 can vary. In the exemplaryembodiment, the thickness 5152 of the top rail 4915 decreases from thestrikeface 4912 toward the rear wall 5123. In many embodiments, due tothe thickness of the top rail, top rail can provide an increase in theoverall bending of strikeface. In some embodiments, the bending ofstrikeface can allow for a 2% to 5% increase of energy.

FIG. 52 illustrates the top rail 4915 and a portion of the rear 4910 ofthe cross-section of the golf club head of FIG. 49, different fromcross-section of golf club head 1200 as shown in FIG. 13. The strikeface4912 further comprises a strikeface angle 5250. The strikeface angle5250 is measured from the strikeface 4912 to the top rail 4915, whereinthe strikeface angle 5250 can range from 70 degrees to 160 degrees or 70degrees to 110 degrees. In some embodiments, strikeface angle can be 70degrees, 75 degrees, 80 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, 140 degrees, 145 degrees, 150 degrees, 155degrees, or 160 degrees.

FIG. 52 further illustrates the top rail 4915 comprising a top railangle 5245. The top rail angle 5245 is measured from rear wall 5123 tothe top rail 4915. In many embodiments, the top rail angle 5245 canrange from 35 degrees to 150 degrees or 70 degrees to 145 degrees. Insome embodiments, top rail angle 5245 can be 35 degrees, 40 degrees, 45degrees, 50 degrees, 55 degrees, 60 degrees, 65 degrees, 70 degrees, 75degrees, 80 degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees,105 degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees.

The rear wall 5123 of the upper region 4911 comprises a height 5180. Theheight 5180 of the rear wall 5123 is measured from the first referencepoint 5122 to the inflection point 5186, wherein the first referencepoint 5122 is positioned at the junction between the top rail 4915 andthe rear wall 5123 parallel to the strikeface 4912. The height 5180 ofthe rear wall 5123 can range from 0.55 inch to 0.60 inch, 0.60 inch to0.70 inch, 0.70 inch to 0.80 inch, 0.80 inch to 0.85, 0.85 inch to 0.90inch, 0.90 inch to 0.95, 0.95 inch to 1 inch or 0.55 inch to 1 inch. Forexample, the height 5180 of the rear wall 5123 can be 0.55 inch, 0.58inch, 0.61 inch, 0.64 inch, 0.67 inch, 0.70 inch, 0.73 inch, 0.76 inch,0.79 inch, 0.82 inch, 0.85 inch, 0.88 inch, 0.91 inch, 0.94 inch, 0.97inch, or 1 inch. In some embodiments, the height 5180 of the rear wall5123 range from 35% to 60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to40%, 35% to 45%, 40% to 50%, 45% to 55%, or 50% to 60% of the totalheight of the golf club head 4900. For example, the height 5180 of therear wall 5123 can be 35%, 38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% ofthe total height of the golf club head 4900.

The rear wall 5123 of the upper region 4911 can also comprise asecondary height 5180A. The secondary height 5180A is measured from theapex 5128 of the top rail 4915 to the inflection point 5186. Thesecondary height 5180A can range from 0.60 inch to 1.2 inch. In someembodiments, the secondary height 5180A can range from 0.60 inch to 0.80inch, 0.80 inch to 1.0 inch, or 1.0 inch to 1.20 inches. For example,the secondary height 5180A can be 0.60 inch, 0.61 inch, 0.64 inch, 0.67inch, 0.70 inch, 0.73 inch, 0.76 inch, 0.79 inch, 0.82 inch, 0.85 inch,0.90 inch, 0.95 inch, 1.0 inch, or 1.2 inches. In some embodiments, thesecondary height 5180A can range from 40% to 75% of the total height ofthe golf club head 4900. For example, the secondary height 5180A can be40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%,54%, 55%, 56%, 60%, 65%, 70%, or 75% of the total height of the golfclub head 4900.

The rear wall 5123 of the upper region 4911 further comprises athickness 5156. The thickness 5156 is the perpendicular distance of therear wall 5123 from the outer surface 4903 to the inner surface 5119.The thickness 5156 of the rear wall 5123 can range from 0.040 inch to0.080 inch. In some embodiments, the thickness 5156 of the rear wall5123 can range from 0.040 inch to 0.060 inch, or 0.060 inch to 0.080inch. For example, the thickness 5156 of the rear wall 5123 can be 0.040inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.051 inch, 0.054 inch, 0.057inch, 0.060 inch, 0.063 inch, 0.066 inch, 0.069 inch, 0.071 inch, 0.074inch, 0.077 inch, or 0.080 inch. In many embodiments, the thickness 5156of the rear wall 5123 is constant throughout. In other embodiments, thethickness 5156 of the rear wall 5123 can vary. In the exemplaryembodiment, the thickness 5156 of the rear wall 5123 is a constant 0.045inch. The thickness of the rear wall allows energy from an impact totransfer to the inflection point to help induce a buckling effect.

The lower region 4913 of the body 4901 comprises a bottom incline 5125,a lower exterior wall 5127, a second reference point 5182, and a thirdreference point 5120. The bottom incline 5125 is below and adjacent theinflection point 5186. The lower exterior wall 5127 is below andadjacent the bottom incline 5125. The second reference point 5182 isdisposed between or positioned at the junction between the bottomincline 5125 and the lower exterior wall 5127. The third reference point5120 is disposed between the lower exterior wall 5127 and the sole 4906.The bottom incline 5125 is angled away from the top rail 4915 and awayfrom the strikeface 4912 in a direction toward the second referencepoint 5182.

In some embodiments, bottom incline 5125 of the lower region 4913comprises a bottom incline length 5129. Bottom incline length 5129 ismeasured from the inflection point 5186 to the second reference point5182. The bottom incline length 5129 can range from 0 inch to 0.55 inch.In some embodiments, the bottom incline length 5129 can range from 0inch to 0.35 inch, or 0.35 inch to 0.55 inch. For example, the bottomincline length 5129 can be 0 inch, 0.05 inch, 0.10 inch, 0.15 inch, 0.20inch, 0.20 inch, 0.25 inch, 0.30 inch, 0.35 inch, 0.40 inch, 0.45 inch,0.50 inch, or 0.55 inch. In some embodiments, the bottom incline length5129 can remain constant from the heel region 4902 to the toe region4904. In other embodiments, the bottom incline length 5129 can vary fromthe heel region 4902 to the toe region 4904, as illustrated in FIG. 49.For example, the bottom incline length 5129 can increase from the heelregion 4902 to the toe region 4904. In other embodiments, the bottomincline length 5129 can decrease from the heel region 4902 to the toeregion 4904.

In some embodiments, the lower region 4913 further comprises a lowerangle 5151 measured from between the bottom incline 5125 to the lowerexterior wall 5127. In some embodiments, the lower angle 5151 can beless than 180 degrees. In a number of embodiments, the lower angle 5151can be 130 degrees to 175 degrees. For example, the lower angle 5151 ofthe lower region 4913 can be 130 degrees, 135 degrees, 140 degrees, 145degrees, 150 degrees, 155 degrees, 160 degrees, 165 degrees, 170degrees, or 175 degrees.

The upper region 4911 and the lower region 4913 of the rear 4910 isseparated by the inflection point 5186. Due to the height of the rearwall, the inflection point 5186 is positioned low on the body 4901. Inmany embodiments, the inflection point 5186 is positioned at least 40%down on the body 4901 below the apex 5128. For example, the inflectionpoint 5186 can be positioned 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%,56%, 58%, or 60% down on the body 4901 below the apex 5128. The lowpositioned inflection point 5186 allows for more leverage on the upperregion 4911 to experience increased bending during impact with a ball,compared to a similar golf club head having a higher inflection pointposition.

The inflection point 5186 comprises an inflection angle 5196 measuredfrom the rear wall 5123 of the upper region 4911, to the bottom incline5125 of the lower region 4913. In some embodiments, the inflection angle5196 can be measured from the rear wall 5123 to the lower exterior wall5127 in the absence of the bottom incline 5125 (i.e., the bottom inclinelength is 0 inch). The inflection angle 5196 of the inflection point5186 can range from at least 95 degrees to 150 degrees. In someembodiments, the inflection angle 5196 can be at least 95 degrees, 100degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125degrees, 130 degrees, 135 degrees, 140 degrees, 145 degrees, or 150degrees. In some embodiments, the inflection angle 5196 can beconsistent from the heel region 4902 to the toe region 4904. In otherembodiments, the inflection angle 5196 can vary from the heel region4902 to the toe region 4904. In many embodiments, the inflection angle5196 allows for the inflection point 5186 to act as a buckling point orplastic hinge upon the golf club head 4900 impacting the golf ball atstrikeface 4912. In other examples of a similar golf club head having aninflection angle, wherein the inflection angle is less than 95 degrees(i.e., 90 degrees, or the bottom incline in oriented approximatelyperpendicular to the strikeface), the inflection angle would impedeenergy transfer and prevent bending at the inflection point.

The rear wall at the inflection point 5186 further comprises a thickness5160. The thickness 5160 at the inflection point 5186 is measuredperpendicularly of the inflection point 5186 from the exterior surface4903 to the interior surface 5119. The thickness 5160 of the inflectionpoint 5186 can range from 0.040 inch to 0.080 inch. In some embodiments,the thickness 5160 of the inflection point 5186 can range from 0.040inch to 0.060 inch, or 0.060 inch to 0.080 inch. For example, thethickness 5160 can be 0.040 inch, 0.045 inch, 0.050 inch, 0.055 inch,0.060 inch, 0.65 inch, 0.065 inch, 0.070 inch, 0.075 inch, or 0.080inch. In many embodiments, the thickness 5160 of the inflection point5186 is constant with the thickness 5156 of the rear wall 5123 and thethickness 5158 of the bottom incline 5125. In other embodiments, thethickness 5160 of the inflection point 5186 can be less than thethickness 5156 of the rear wall 5123 and the thickness 5158 of thebottom incline 5125. The thickness 5160 of the inflection point 5186being consistent with or less than the thickness 5156, 5158 of the rearwall 5123 and the bottom incline 5125 allows for more uniform energytransfer and bending.

The body 4901 of the golf club head 4900 further comprises a minimumdistance 5116, and a maximum distance 5118. The minimum distance 5116 ofthe body 4901 is measured as the perpendicular distance from theexterior surface 4903 of the strikeface 4912 in the upper region 4911 tothe exterior surface 4903 of the rear wall 5123. The minimum distance5116 can range from 0.20 inch to 0.44 inch. In some embodiments, theminimum distance 5116 can range from 0.20 inch to 0.30 inch, or 0.30inch to 0.44 inch For example, the minimum distance 5116 can be 0.20inch, 0.22 inch, 0.24 inch, 0.26 inch, 0.28 inch, 0.30 inch, 0.32 inch,0.34 inch, 0.36 inch, 0.38 inch, 0.40 inch, 0.42 inch, or 0.44 inch. Themaximum distance 5118 of the body 4901 is measured as the perpendiculardistance from the exterior surface 4903 of the strikeface 4912 in thelower region 4913 to the exterior surface 4903 of the third referencepoint 5120. The maximum distance 5118 can range from 0.60 inch to 1.0inch. In some embodiments, the maximum distance 5118 can range from 0.60inch to 0.80 inch, or 0.80 inch to 1.0 inch. For example, the maximumdistance 5118 can be 0.60 inch, 0.64 inch, 0.68 inch, 0.72 inch, 0.76inch, 0.80 inch, 0.84 inch, 0.88 inch, 0.90 inch, 0.92 inch, 0.94 inch,0.96 inch, or 1.0 inch.

The body 4901 of the golf club head 4900 further comprises an internalcavity distance 5114 as illustrated in FIG. 53. The internal cavitydistance 5114 is measured as the perpendicular distance from theexterior surface 4903 of the strikeface 4912 in the lower region 4913 tothe interior surface 5119 of the rear wall 5123. The internal cavitydistance 5114 can range from 0.40 inch to 0.80 inch. In someembodiments, the internal cavity distance 5114 can range from 0.40 inchto 0.60 inch, or 0.60 inch to 0.80 inch. For example, the internalcavity distance 5114 can be 0.40 inch, 0.44 inch, 0.48 inch, 0.52 inch,0.56 inch, 0.60 inch, 0.64 inch, 0.68 inch, 0.72 inch, 0.76 inch, or0.80 inch.

As illustrated in FIG. 49-52, the golf club head 4900 can be a hollow,or at least partially hollow body comprising an internal cavity 4916.Internal cavity 4916 of the body 4901 comprises a volume. The volume ofthe internal cavity 4916 can range from 1.20 inch³ (19.66 cm³) to 2.0inch³ (32.77 cm³). In some embodiments, the internal cavity 4916 canrange from 1.20 inch³ (19.66 cm³) to 1.6 inch³ (26.22 cm³), or 1.6 inch³(26.22 cm³) to 2.0 inch³ (32.77 cm³). For example, the internal cavity4916 can comprise a volume of 1.20 inch³ (19.66 cm³), 1.30 inch³ (21.30cm³), 1.40 inch³ (22.94 cm³), 1.50 inch³ (24.58 cm³), 1.60 inch³ (26.22cm³), 1.70 inch³ (27.86 cm³), 1.80 inch³ (29.50 cm³), 1.90 inch³ (31.14cm³), or 2.0 inch³ (32.77 cm³). Similarly, the solid portion of the body4900, void of the cavity 4916, further comprises a material volume. Thematerial volume of the body can range from 3.0 inch³ (49.16 cm³) to 4.0inch³ (65.55 cm³). In some embodiments, the material volume of the bodycan range from 3.0 inch³ (49.16 cm³) to 3.5 inch³ (57.35 cm³), or 3.5inch³ (57.35 cm³) to 4.0 inch³ (65.55 cm³). For example, the materialvolume of the body can be 3.0 inch³ (40.97 cm³), 3.10 inch³ (50.80 cm³),3.20 inch³ (52.44 cm³), 3.30 inch³ (54.08 cm³), 3.40 inch³ (55.72 cm³),3.50 inch³ (57.35 cm³), 3.60 inch³ (58.99 cm³), 3.70 inch³ (60.63 cm³),3.80 inch³ (62.27 cm³), 3.90 inch³ (63.91 cm³), or 4.0 inch³ (65.55cm³).

In many embodiments, the internal cavity 4916 of the body 4900 can bevoid of any substance. In other embodiments, the internal cavity 4916 ofthe body 4900 can comprise a polymer (not pictured), wherein the polymercan at least partially fill the internal cavity 4916. The polymer can bepolyethylene terephthalate, high-density polyethylene, polyvinylchloride, polycarbonate, polypropylene, other thermoplastics, compositespolymers or any combination thereof. The polymer can fill 10% to 80%,10% to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%,10% to 40%, 30% to 60%, or 40% to 80% of the internal cavity of thebody. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%, 35%,40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internalcavity of the body. In some embodiments, the polymer fills 80% of theinternal cavity 4916 of the body 4901.

The polymer to at least partially fill the internal cavity 4916 of thebody 4901 comprises a specific gravity ranging from 0.05 to 4. In someembodiments, the specific gravity ranges from 0.05 to 0.10, 0.10 to0.50, 0.50 to 1.0, 1.0 to 2.0, or 2.0 to 4.0. For example, the specificgravity of the polymer can be 0.50, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, or4.0. In some embodiments, the specific gravity of the polymer isproportional to the mass of the polymer, wherein 1 specific gravity ofthe polymer is equal to 1 gram. Similarly, in those exemplaryembodiments, the volume is proportional to the polymer specific gravity,wherein 1 specific gravity of the polymer is equal to 1 cc. In otherembodiments, the volume is not proportional to the specific gravity ofthe polymer. For example, the ratio of the polymer specific gravity tothe polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4cc, 4:1 cc, 4:2 cc, or 4:3 cc.

In some embodiments, as illustrated in FIG. 54, the golf club head 4900can further comprise a first aperture 5134 located on the toe region4904 and a second aperture 5136 located in a hosel of the golf club head4900. The first aperture 5134 is configured to receive a toe weight (notpictured), wherein the toe weight can range from 2 grams to 7 grams. Insome embodiments, the toe weight can range from 2 grams to 5 grams, or 5grams to 7 grams. For example, the toe weight can be 2 grams, 3 grams, 4grams, 5 grams, 6 grams, or 7 grams. The second aperture 5136 isconfigured to receive a tip weight (not pictured), wherein the tipweight can range from 2 grams to 7 grams. In some embodiments, the tipweight can range from 2 grams to 5 grams, or 5 grams to 7 grams. Forexample, the tip weight can be 2 grams, 3 grams, 4 grams, 5 grams, 6grams, or 7 grams. In many embodiments, the first aperture 5134 and thesecond aperture 5136 can further be configured to receive the polymer.The first aperture 5134 can receive 1 gram to 9 grams of polymer (e.g.,1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6 grams, 7 grams, 8 grams,or 9 grams). Similarly, the second aperture 5136 can receive 1 gram to 9grams of polymer (e.g., 1 gram, 2 grams, 3 grams, 4 grams, 5 grams, 6grams, 7 grams, 8 grams, or 9 grams). The toe and tip weight, and thepolymer housed within the first aperture 5134 and the second aperture5136 can affect the swing weight to optimize CG and MOI.

The internal cavity 4916 of the body 4901 further comprises interiorsurface 5119. In some embodiments, the interior surface 5119 of the rear4910 is a planar and smooth surface. In other embodiments as illustratedin FIG. 52, the interior surface 5119 of the internal cavity 4916 of therear 4910 comprises a plurality of ribs 4952. The plurality of ribs 4952extend in a direction from top rail 4915 toward the sole 4906. Theplurality of ribs 4952 can be located anywhere on interior surface 5119of the rear 4910. In some examples, the plurality of ribs 4952 can bepositioned onto a portion of interior surface 5119 of the lower exteriorwall 5127. In other examples, the plurality of ribs 4952 can bepositioned on a portion of the interior surface 5119 of the rear wall5123. In some embodiments, the plurality of ribs 4952 can be positionedon a portion of the interior surface 5119 of the rear 4910 and canextend into another portion of the rear 4910. For example, the pluralityof ribs 4952 are positioned on a portion of the interior surface 5119 ofthe rear wall 5123 and can extend up to at least a portion of the bottomincline 5125, or at least a portion of the lower exterior wall 5127. Theplurality of ribs 4952 can comprise between one to eight ribs. Forexample, the plurality of ribs 4952 can comprise one rib, two ribs,three ribs, four ribs, five ribs, six ribs, seven ribs, or eight ribs.In embodiments having one or more plurality of ribs 4952, the pluralityof ribs 4952 can be spaced equidistance from each other or moreconcentrated near the heel region 4902, toe region 4904, top rail 4915,or sole 4906. The plurality of ribs 4952 and the location of theplurality of ribs 4952 can help optimize the frequency and amplitude ofsound response.

In some embodiments, body 4901 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 4901can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 4912 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 4912 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, the body 4901 can comprise the same material as thestrikeface 4912. In some embodiments, the body 4901 can comprise adifferent material than the strikeface 4912.

FIG. 56 illustrates a back perspective view of an embodiment of golfclub head 5600 and FIG. 57 illustrates a back heel-side perspective viewof golf club head 5600 according to the embodiment of FIG. 56. In someembodiments, golf club head 5600 can be similar to golf club head 1000(FIG. 10), golf club head 2200 (FIG. 22), golf club head 2700 (FIG. 27),golf club head 3200 (FIG. 32), golf club head 3700 (FIG. 37), and/orgolf club head 4400 (FIG. 44). Golf club head 5600 can be an iron-typegolf club head.

Golf club head 5600 comprises a body 5601. In some embodiments, body5601 can be similar to body 1001 (FIG. 10), body 2201 (FIG. 22), body2701 (FIG. 27), body 3201 (FIG. 32), body 3701 (FIG. 37), and/or body4401 (FIG. 44). The body 5601 comprises an exterior surface 5603, astrikeface 5612, a heel region 5602, a toe region 5604 opposite the heelregion 5602, a sole 5606, a top rail 5615, and a rear 5610. Thestrikeface 5612, sole 5606, top rail 5615, and rear 5610 of the body5601 together form an internal cavity 5616. Furthermore, the golf clubhead 5600 can be divided into an upper region 5611 and a lower region5613 (see FIG. 58).

The rear 5610 of the golf club head 5600 can comprise an indention 5630that alters the deflection and/or weighting of the club head. The rear5610 of the golf club head can further comprise a ledge 5825 or stepwall below the indention 5630. The rear 5610 further comprises an upperperimeter portion 5609, which extends along the top rail 5615 and wrapsdown the sides of the toe region 5604 and heel region 5602. A toe slit5666 and a heel slit 5662 are each positioned between a part of theupper perimeter portion 5609 and a lower exterior wall 5727 of a lowerregion 5613 of the club head 5600, allowing structural bending betweenupper and lower halves of the club head 5600. This bending allowed bythe toe slit 5666 and heel slit 5662 results in greater deflection ofthe strikeface 5612 over a club head without these slits. The club head5600 can further comprise a vibration damping layer 5878 on an interiorsurface 5819 of the strikeface 5612. In some embodiments, the internalcavity 5616 can be filled or partially filled with a polymer material.

Body 5601 of FIGS. 56-62 comprises a blade length. The blade length forbody 5601 can be measured similar to blade length 3725 as shown anddescribed in FIG. 43 (i.e., a measurement parallel to the flat surfaceof the strikeface 3712, from a toe edge 3726 of the strikeface 3712, tostrikeface end 3727 before the strikeface 3712 integrally curves intothe hosel). The blade length of the body 5601 can range from 2.50 inches(6.35 cm) to 2.90 inches (7.37 cm). For example, in some embodiments,the body 3701 can comprise a blade length of 2.50 inch (6.35 cm), 2.54inch (6.45 cm), 2.58 inch (6.55 cm), 2.62 inch (6.65 cm), 2.66 inch(6.76 cm), 2.70 inch (6.86 cm), 2.74 inch (6.96 cm), 2.78 inch (7.06cm), 2.82 inch (7.16 cm), 2.86 inch (7.264 cm), or 2.90 inch (7.37 cm).

The sole can comprise a cascading sole portion of the sole, as describedin greater detail below. As shown in FIG. 60, a deflection feature ofthe golf club head 5600 can be a uniform thinned region 6060, located atthe sole 5606 and stretching between the rear 5610 of the body 5601 andthe strikeface 5612, toward the cascading sole portion of the sole. Inthe illustrated embodiment, the uniform thinned region 6060 comprises asole thickness measured perpendicular from the exterior surface 5603 toan interior surface 5819 at the uniform thinned region 6060, which canremain constant from the bottom of the strikeface 5612 to adjacent thecascading sole portion of the sole. In some embodiments, the solethickness of the uniform thinned region 6060 can be thinner than aconventional sole. For example, in some embodiments, the sole thicknessof the uniform thinned region 6060 may range from approximately 0.040inch to 0.080 inch. In other embodiments, the sole thickness of theuniform thinned region 6060 may be within the range of 0.040 inch to0.050 inch, 0.050 inch to 0.060 inch, 0.060 inch to 0.070 inch, 0.070inch to 0.080 inch, 0.040 inch to 0.055 inch, 0.045 inch to 0.060 inch,0.050 inch to 0.065 inch, 0.055 inch to 0.070 inch, 0.060 inch to 0.075inch, or 0.065 inch to 0.080 inch. For example, the sole thickness ofthe uniformed thinned region 4860 can be 0.040 inch, 0.045 inch, 0.050inch, 0.060 inch, 0.065 inch, 0.070 inch, 0.075 inch, or 0.080 inch.

FIG. 58 illustrates a cross-section of golf club head 5600 along thecross-sectional line LVIII-LVIII in FIG. 56, according to oneembodiment. As seen in FIG. 58, strikeface 5612 comprises a high region5876, a middle region 5874, and a low region 5872.

The strikeface 5612 of the body 5601 further comprises a thickness 5854measured perpendicularly to the strikeface 5612 from the exteriorsurface 5603 to an interior surface 5819. The thickness 5854 of thestrikeface 5612 can range from 0.040 inch to 0.100 inch. For example,the thickness 5854 of the strikeface 4412 can be 0.040 inch, 0.045 inch,0.050 inch, 0.055 inch, 0.060 inch, 0.065 inch, 0.070 inch, 0.075 inch,0.080 inch, 0.085 inch, 0.090 inch, 0.095 inch, or 0.100 inch. In someembodiments, thickness 5854 of the strikeface 5612 can vary from theheel region 5602 to the toe region 5604, and/or from the top rail 5615to the sole 5606. For example, the thickness 5854 of the strikeface 5612can be greatest at the central portion near the middle region 5874 ofthe strikeface 5612, and taper along the periphery near the high region5876 and the low region 5872 of strikeface 5612. In many embodiments,the center of the strikeface 5612 can have a thickness 5854 of 0.090inch and the periphery of the strikeface 5612 can have a thickness 5854of 0.070 inch. In other examples, the thickness 5854 can increase,decrease, or any variation thereof starting at the central region nearthe middle region 5874 of the strikeface 5612 and extending toward theperiphery near the high region 5876 and the low region 5872.

The upper region 5611 of rear 5610 comprises the upper perimeter portion5609, the indention 5630, and the ledge 5825. The upper perimeterportion comprises the top rail of the club head and wraps down around alength of the toe and heel regions of the club head. The upper perimeterportion 5609 extends along a top edge of the golf club head 5600 fromthe heel region 5602 to the toe region 5604. In the toe region 5604 theupper perimeter portion 5609 extends down along a perimeter of the toeregion 5604. In some embodiments, the upper perimeter portion 5609extends roughly halfway down along the perimeter of the toe region 5604.The upper perimeter portion abuts the indention. The upper perimeterportion 5609 of the rear 5610 can provide perimeter weighting for theclub head 5600. In addition, the upper perimeter portion 5609 allowsstresses in the top rail 5615 to be dissipated into the rear 5610 of theclub head 5600.

The indention 5630 is located on the exterior surface 5603, below theupper perimeter portion and above the lower region 5613 of the club head5600. The indention 5630 of the rear 5610 extends inwards towards thestrikeface of the golf club head 5600. The indention 5630 is located inthe upper portion 5611 of the club head 5600. In some embodiments, theindention 5630 is located primarily in an upper half of the golf clubhead 5600. The indention 5630 is bounded on its top, toe, and heel sidesby the upper perimeter portion 5609. The indention 5630 is bounded onits bottom side by the ledge 5825.

The ledge 5825 extends in a direction generally from the heel region5602 towards the toe region 5604. The ledge 5825 helps form a lowerboundary of the indention 5630. The ledge 5825 can be located at variousheights above the ground plane 10 when the club head 5600 is at addressposition. The ledge 5825 can comprise multiple segments, wherein eachsegment is located at a different height above the ground plane 10, asshown in the rear view of FIG. 56. For example, the ledge 5825 cancomprise a segment located in the toe region 5604 that is higher fromthe ground plane 10 than a segment located, at least partially, in theheel region 5602.

The ledge 5825 of the rear 5610 of the club head 5600 can be positionedin a plane roughly perpendicular to the strikeface 5612 plane. The ledge5825 runs the length of the club head 5600 from the heel region 5602 tothe toe region 5604. The ledge 5825 can also be thought of as a ledge orgroove. At the heel end the ledge 5825 can blend into the heel slit5662. At the toe end, the ledge 5825 can blend into the toe slit 5666.

The ledge 5825 can be angled with respect to the ground plane 10 at aledge angle (not illustrated). In some embodiments, the ledge angle,measured from the ledge 5825 to ground plane 10, can range from 15degrees to 45 degrees. In some embodiments, the ledge angle can be 15degrees, 16 degrees, 17 degrees, 18 degrees, 19 degrees, 20 degrees, 21degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, or45 degrees.

The toe and heel slits 5666, 5662 are positioned on the rear 5610 of theclub head 5600 roughly half way upward from the ground plane 10 towardsthe top rail 5615. The toe and heel slits 5666, 5662 span short lengthsacross the toe and heel regions 5604, 5604 of the club head 5600,respectively. The toe and heel slits 5666, 5662 extend from either endof the ledge 5825. The toe slit 5666 is positioned in the toe region5604 between the upper perimeter portion 5609 and the lower region 5613of the club head 5600. The heel slit 5662 is positioned in the heelregion 5602 between the upper perimeter portion 5609 next to andadjacent the hosel.

The toe slit 5666 and the heel slit 5662 are oriented in a toe-to-heeldirection. The toe slit 5666 can be positioned between approximatelyhalf way and approximately ⅔ of the way upwards from the ground plane 10towards the top rail 5615, measured parallel to the strikeface 5612. Theheel slit 5662 can also be positioned between approximately half way upand approximately ⅔ of the way upwards from the ground plane 10 towardsthe top rail 5615. In some embodiments, the heel slit 5662 is positionedlower with respect to the ground plane 10 than the toe slit 5666. Inthese embodiments, the upper perimeter portion 5609 extends lower in theheel region 5602 than in the toe region 5604.

The toe slit 5666 has a depth 6267 such that a deepest surface of theslit 5666 blends into the indention 5630. The toe slit depth 6267 can bemeasured from the outer surface of the upper perimeter portion a lowestpoint inside the toe slit. The toe slit depth 6267 can range between0.05 inch and 0.20 inch. For example, the toe slit depth 6267 can rangebetween 0.05 inch and 0.15 inch, or 0.15 inch and 0.20 inch. A toe slitheight 5668 can be measured in a direction generally orthogonal to theground plane from the intersection of the upper perimeter portion 5609and the toe slit 5666 to the intersection of the ledge 5825 and the toeslit 5666. The toe slit height 5668 can range between 0.10 inch and 0.30inch. For example, the toe slit height 5668 can range between 0.15 inchand 0.17 inch, 0.10 inch and 0.15 inch, 0.15 inch and 0.20 inch, or 0.20inch and 0.30 inch. The toe slit 5666 can comprise a length 5669 betweenthe outer edge of the toe region 5604 to the indention 5630 where thetoe slit 5666 terminates, as shown in FIG. 56. The toe slit length 5669can range between 0.318 inch and 0.418 inch. For example, the toe slitlength 5669 can be 0.318 inch, 0.320 inch, 0.330 inch, 0.340 inch, 0.350inch, 0.360 inch, 0.368 inch, 0.370 inch, 0.380 inch, 0.390 inch, 0.400inch, 0.0410 inch, or 0.418 inch. The dimensions of the toe slit 5666can affect the deflection of the strikeface 5612, as described below.

The heel slit 5662 is similar in depth and orientation to the toe slit5666. However, in some embodiments, the angular orientation of the heelslit 5662 with respect to the ground plane differs slightly from theangular orientation of the toe slit 5666. In some embodiments, the heelslit 5662 does not extend to a heel-most point of the club head 5600. Aheel slit height 5664 can be measured in a direction generallyorthogonal to the ground plane from the intersection of the upperperimeter portion 5609 and the heel slit 5662 to the intersection of theledge 5825 and the heel slit 5662. The heel slit height 5664 can rangebetween 0.10 inch and 0.30 inch. For example, the heel slit height 5664can range between 0.13 inch and 0.16 inch, 0.10 inch and 0.15 inch, 0.15inch and 0.20 inch, or 0.20 inch and 0.30 inch. The heel slit cancomprise a length 5665, measured from adjacent an edge of the perimeterportion towards the heel region, as shown in FIG. 56. The heel slitlength 5665 can be longer than the toe slit length 5669. In otherembodiments, the heel and toe slits are the same length. The heel slitlength 5665 can range between 0.325 inch and 0.425 inch. For example,the heel slit length 5665 can be 0.325 inch, 0.330 inch, 0.335 inch,0.340 inch, 0.345 inch, 0.350 inch, 0.355 inch, 0.360 inch, 0.365 inch,0.370 inch, 0.375 inch, 0.380 inch, 0.385 inch, 0.390 inch, 0.395 inch,0.400 inch, 0.405 inch, 0.410 inch, 0.415 inch, 0.420 inch, or 0.425inch. The dimensions of the heel slit 5662 can affect the deflection ofthe strikeface 5612, as described below.

In the lower region 5613 of the club head 5600, the body 5601 extends agreater perpendicular distance from the strikeface 5612 than the upperperimeter portion 5609 or the indention 5630. The lower region 5613comprises, in part, a solid region adjacent the sole 5606 and the rear5610 of the club head 5600. The solid region provides perimeterweighting to the club head 5600. The solid region is bounded by the sole5606 and a lower exterior wall 5727. A front edge of the solid regiondefines a part of the internal wall of the internal cavity 5616.

The cross-section of golf club head 5600 in FIG. 58 further illustratesthe rear 5610. The rear 5610 can be divided and understood with respectto the upper region 5611 and the lower region 5613 of the club head5600. The upper region 6511 of the rear comprises the upper perimeterportion 5609 and the indention 5630, including the ledge 5825. Asillustrated in FIG. 58, the upper perimeter portion 5609 comprises thetop rail 5615, a rear wall 5723, and a top wall 5719. The indention 5630is formed by the top wall 5719 of the upper perimeter portion, anindention wall 5821, and a ledge 5825.

As seen in FIG. 58, from a cross-sectional view, the upper region 5611of rear 5610 comprises the top rail 5615, the rear wall 5723, the topwall 5719, the indention wall 5821, and the ledge 5825. The rear wall5723 of rear 5610 is located below and adjacent to the top rail 5615.The top wall 5719 of rear 5610 is located below and adjacent to the rearwall 5723. The indention wall 5821 is located below and adjacent to thetop wall 5719. The ledge 5825 is located below and adjacent to theindention wall 5821. In short, the top wall 5719 and the ledge 5825 areangled towards the strikeface and connect to the indention wall 5821, toform the indention 5630. The upper region 5611 further comprises a firstreference point 5722 located between top rail 5615 and rear wall 5723, asecond reference point 5782 located between rear wall 5723 and top wall5719, a first inflection point 5786 located between top wall 5719 andthe indention wall 5821, a second inflection point 5792 located betweenthe indention wall 5821 and the ledge 5825, and a third inflection point5794 located between the ledge 5825 and the lower region 5613.

In some embodiments, top rail 5615 of the upper perimeter portion can bea flatter and taller top rail or skirt than in irons known to oneskilled in the art. The flatter and taller rail can compensate formishits of strikeface 5612 to increase playability off the tee. In someembodiments, the length of top rail 5615, measured from heel region 5602to toe region 5604, can be 70% to 95% of the length of golf club head5600. In many embodiments, indention 5630 comprises a top rail boxspring design. For some fairway iron-type golf club head embodiments,indention 5630 can be a reverse scoop or indentation of rear 5610 withbody 5601 comprising a greater thickness toward sole 5606. In manyembodiments, the top rail of the upper perimeter portion and theindention 5630 provide an increase in the overall bending of strikeface5612. In some embodiments, the bending of strikeface 5612 can allow fora 2% to 5% increase of energy. The indention 5630 allows for strikeface5612 to be thinner and allow additional overall bending.

The top rail 5615 of the upper perimeter portion comprises a thickness6052. The thickness 6052 of the top rail 5615 can range from 0.040 inchto 0.080 inch. For example, the thickness 6052 of the top rail 5615 canbe 0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch, 0.051 inch, 0.054inch, 0.057 inch, 0.060 inch, 0.063 inch, 0.066 inch, 0.069 inch, 0.071inch, 0.074 inch, 0.077 inch, or 0.080 inch. In many embodiments, thethickness 6052 of the top rail 5615 is constant throughout. In otherembodiments, the thickness 6052 of the top rail 5615 can vary. In theexemplary embodiment, the thickness 6052 of the top rail 5615 decreasesfrom the strikeface 5612 toward the rear wall 5823. In many embodimentsdue to the thickness 6052 of the top rail, top rail 5615 can provide anincrease in the overall bending of strikeface 5612.

FIG. 59 illustrates a view of top rail 5615 and a portion of rear 5610of the cross-section of golf club head 5600 of FIG. 56, along across-sectional line LVIII-LVIII in FIG. 56 that is similar to thecross-section of FIG. 58. In many embodiments, golf club head 5600comprises a rear angle 5940, a top rail angle 5945, and a strikefaceangle 5950. Rear angle 5940 is measured from top wall 5819 to rear wall5823 of upper region 5611. In many embodiments, rear angle 5940 canrange from 70 degrees to 140 degrees. In some embodiments, rear angle5940 can be 70 degrees, 75 degrees, 80 degrees, 85 degrees, 90 degrees,100 degrees, 105 degrees, 110 degrees, 115 degrees, 120 degrees, 125degrees, 130 degrees, 135 degrees, or 140 degrees. In some embodiments,the rear angle 5940 is approximately 122 degrees.

The strikeface 5612 further comprises a strikeface angle 5950.Strikeface angle 5950 is measured from the strikeface 5612 to the toprail 5615, wherein the strikeface angle 5950 can range from 70 degreesto 160 degrees or 70 degrees to 110 degrees. In some embodiments,strikeface angle 5950 can be 70 degrees, 75 degrees, 80 degrees, 90degrees, 95 degrees, 100 degrees, 105 degrees, 110 degrees, 115 degrees,120 degrees, 125 degrees, 130 degrees, 135 degrees, 140 degrees, 145degrees, 150 degrees, 155 degrees, or 160 degrees. In some embodiments,the strikeface angle 5950 is approximately 90 degrees.

FIG. 59 further illustrates the top rail 5615 comprising a top railangle 5945. The top rail angle 5945 is measured from rear wall 5823 tothe top rail 5615. In many embodiments, the top rail angle 5945 canrange from 70 degrees to 160 degrees or 90 degrees to 110 degrees. Insome embodiments, top rail angle 5945 can be 70 degrees, 75 degrees, 80degrees, 85 degrees, 90 degrees, 95 degrees, 100 degrees, 105 degrees,110 degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, or 160degrees. In some embodiments, the top rail angle 5945 is approximately131 degrees.

The rear wall 5723 extends from the first reference point 5722 to thesecond reference point in an orientation roughly parallel to thestrikeface. The rear wall 5723 connects the top rail and the top wall5719. The rear wall 5823 of the upper region 5611 comprises a height5880. The height 5880 of the rear wall 5823 is measured from the firstreference point 5722 to the second reference point 5782. The height 5880of the rear wall 5823 can range from 0.055 inch to 0.060 inch, 0.060inch to 0.070 inch, 0.070 inch to 0.080 inch, 0.080 in to 0.085 or 0.55inch to 0.85 inch. For example, the height 4680 of the rear wall 4623can be 0.55 inch, 0.58 inch, 0.61 inch, 0.64 inch, 0.67 inch, 0.70 inch,0.73 inch, 0.76 inch, 0.79 inch, 0.82 inch, or 0.85 inch. In someembodiments, the height 5880 of the rear wall 4623 range from 35% to60%, 35% to 45%, 45% to 68%, 40% to 55%, 30% to 40%, 35% to 45%, 40% to50%, 45% to 55%, or 50% to 60% of the total height of the golf club head5600. For example, the height 5880 of the rear wall 5823 can be 35%,38%, 41%, 44%, 47%, 50%, 53%, 56%, or 60% of the total height of thegolf club head 5600.

The rear wall 5823 of the upper region 5611 can also comprise a height5680A. The height 5680A is measured from the apex 5828 of the top rail5615 to the second reference point 5782. The height 5880A can range from0.60 inch to 1.0 inch. For example, the height 5880A can be 0.60 inch,0.61 inch, 0.64 inch, 0.67 inch, 0.70 inch, 0.73 inch, 0.76 inch, 0.79inch, 0.82 inch, 0.85 inch, 0.90 inch, 0.95 inch, or 1.0 inch. In someembodiments, the height 5880A can range from 40% to 75% of the totalheight of the golf club head 5600. For example, the height 5880A can be40%, 44%, 47%, 50%, 53%, 56%, 60%, 65%, 70%, or 75% of the total heightof the golf club head 5600.

The rear wall 5823 of the upper region 5611 further comprises a rearwall thickness 5856. The rear wall thickness 5856 is the perpendiculardistance of the rear wall 5823 from the outer surface 5603 to the innersurface 5619 of the internal cavity 5630. The rear wall thickness 5856can range from 0.040 inch to 0.080 inch. For example, the rear wallthickness 5856 can be 0.040 inch, 0.043 inch, 0.046 inch, 0.049 inch,0.051 inch, 0.054 inch, 0.057 inch, 0.060 inch, 0.063 inch, 0.066 inch,0.069 inch, 0.071 inch, 0.074 inch, 0.077 inch, or 0.080 inch. In manyembodiments, the rear wall thickness 5856 is constant throughout. Inother embodiments, the rear wall thickness 5856 5823 can vary. In theexemplary embodiment, the rear wall thickness 5856 is a constant 0.05inch. The rear wall thickness 5856 allows energy from an impact totransfer to the inflection point 5886 to help induce a buckling effect.

The top wall 5719 is angled toward the strikeface and away from the toprail 5615 in a direction toward the first inflection point 5786. The topwall 5719 extends from the second reference point 5782 to the firstinflection point 5786. The described configuration of the rear wall 5723and top wall 5719 allows increased bending of the top rail 5615 of theclub head 5600 on impact with a golf ball, compared with a club headdevoid of the described rear and top wall configuration. The top wall5719 connects to the indention wall 5821 at the first inflection point5786.

The indention 5630 is formed by the top wall 5719, the indention wall5821, and the ledge 5825. In some embodiments, the indention wall 5821can be roughly planar. In some embodiments, the indention wall 5821 cancomprise an at least partially curved profile, when viewed from across-sectional view, as shown in FIG. 58. An indention wall thickness5858 is measured perpendicularly from the exterior surface 5603 to theinterior surface 5819 at a point along the indention wall 5821 betweenthe first inflection point 5786 and the second inflection point 5792.The indention wall thickness 5858 can range from 0.040 inch, to 0.080inch. For example, the indention wall thickness 5858 can be 0.040 inch,0.045 inch, 0.050 inch, 0.055 inch, 0.060 inch, 0.65 inch, 0.065 inch,0.070 inch, 0.075 inch, or 0.080 inch. In many embodiments, theindention wall thickness 5858 is constant with the rear wall thickness5856 and a ledge thickness 5860. In other embodiments, the indentionwall thickness 5858 can be less than the rear wall thickness 5856 andthe ledge thickness 5860. The indention wall thickness 5858 beingconsistent with or less than the thickness 5823, 5860 of the rear wall5723 and the ledge 5825 allows for more uniform energy transfer andbending.

As best understood from a rear view, such as FIG. 56, the indention wall5821 can cover a surface area between 10% and 40% of the surface area ofthe rear 5610. For example, the indention wall 5821 can cover a surfacearea between 10% and 20%, 20% and 30%, or 30% and 40% of the surfacearea of the rear 5610. In some embodiments, the indention wall 5821 cancover a surface area approximately 29% of the surface area of the rear5610.

A height 5888 of the indention 5630 is measured perpendicular to theground plane 10 from the second reference point 5782 to the thirdinflection point 5794. The height 5888 of the indention 5630 can rangefrom 0.15 inch to 1.1 inch. For example, the height 5888 of theindention 5630 can range from 0.15 inch to 0.30 inch, 0.30 inch to 0.45inch, 0.45 inch to 0.60 inch, 0.60 inch to 0.75 inch, 0.75 inch to 0.90inch, or 0.90 inch to 1.0 inch. For example, the height 5888 of theindention 5630 can be approximately 0.21 inch in the heel region 5602,approximately 0.63 inch in a center of the club head between the heelregion 5602 and the toe region 5604, and approximately 0.98 inch in thetoe region 5604. In some embodiments, the maximum height 5888 of theindention is between 0.80 inch and 1.1 inch.

The second inflection point 5792 comprises a second inflection anglemeasured from the indented wall 5721 to the ledge 5825. The secondinflection angle of the second inflection point 5792 can range from atleast 95 degrees to 150 degrees. In some embodiments, the secondinflection angle 5796 can be at least 95 degrees, 100 degrees, 105degrees, 110 degrees, 115 degrees, 120 degrees, 125 degrees, 130degrees, 135 degrees, 140 degrees, 145 degrees, or 150 degrees. In someembodiments, the second inflection angle can be consistent from the heelregion 5602 to the toe region 5604. In other embodiments, the secondinflection angle 5796 can vary from the heel region 5602 to the toeregion 5604. In many embodiments, the second inflection angle 5796allows for the second inflection point 5686 to act as a buckling pointor plastic hinge upon the golf club head 5600 impacting the golf ball atstrikeface 5712.

As illustrated in FIG. 58, in some embodiments, the ledge comprises aledge width 5829. The ledge width 5829 is measured along the ledge 5825from the second inflection point 5792 to the third inflection point5794. The ledge width 5829 can range from 0.088 inch to 0.128 inch. Forexample, the ledge width 5829 can be 0.090, 0.094 inch, 0.098 inch,0.100 inch, 0.104 inch, 0.108 inch, 0.110 inch, 0.112 inch, 0.114 inch,0.118 inch, 0.120 inch, 0.124 inch, or 0.128 inch. In some embodiments,the ledge width 5829 can remain constant from the heel region 5602 tothe toe region 5604. In other embodiments, the ledge width 5829 can varyfrom the heel region 5602 to the toe region 5604. For example, the ledgewidth 5829 can increase from the heel region 5602 to the toe region5604. In other embodiments, the ledge width 5829 can decrease from theheel region 5602 to the toe region 5602.

The ledge 5825 comprises a ledge thickness measured perpendicularly fromthe exterior surface 5603 to the interior surface 5819 at a point alongthe ledge 5825 between the second inflection point 5792 and the thirdinflection point 5794. The ledge thickness can be similar to theindented wall thickness.

The upper region 5611 and the lower region 5613 of the rear 5610 areseparated by the third inflection point 5794. In many embodiments, thethird inflection point 5794 is positioned at least 40% down on the body5601 below the apex 5828. For example, the third inflection point 5694can be positioned 40%, 42%, 44%, 46%, 48%, 50%, 52%, 54%, 56%, 58%, 60%,62%, 64%, 66%, 68%, or 70% down on the body 5601 below the apex 5828.The low positioned third inflection point 5794 allows for more leverageon the upper region 5611 to experience increased bending during impactwith a ball, compared to a similar golf club head having a higherinflection point position.

The lower region 5613 of the body 5601 begins at the third inflectionpoint 5794 and comprises a lower exterior wall 5827. The lower exteriorwall 5827 extends from the first inflection point 5794 to the sole 5606.The lower exterior wall 5827 can be angled with respect to thestrikeface. The lower region 5613 comprises a height measured from theground plane 5703 to the third inflection point 5794 adjacent a lowestend of the ledge 5825. The lower region 5613 height can range between0.40 inch and 1.20 inch. For example, the lower region 5613 height canrange between 0.40 inch and 0.70 inch, 0.60 inch and 0.80 inch, 0.70inch and 0.90 inch, 0.80 inch and 1.00 inch, 0.90 inch and 1.10 inch, or1.00 inch and 1.20 inch.

A third inflection angle 5851 is measured between the ledge 5825 and thelower exterior wall 5727, at the third inflection point 5794. In someembodiments, the third inflection angle 5851 can be less than 160degrees. In a number of embodiments, the third inflection angle 5851 canbe 90 degrees to 175 degrees. For example, the third inflection angle5851 can be 90 degrees, 95 degrees, 100 degrees, 105 degrees, 110degrees, 115 degrees, 120 degrees, 125 degrees, 130 degrees, 135degrees, 140 degrees, 145 degrees, 150 degrees, 155 degrees, 160degrees, 165 degrees, 170 degrees, or 175 degrees.

The lower exterior wall 5727 is located in the lower region 5613 of theclub head 5600. The lower exterior wall 5727 extends downward from thethird inflection point 5794 at an edge of the ledge 5825 to the sole ofthe club head 5600. A section of the lower exterior wall 5727 forms anouter rear edge of the solid region of the lower region 5613. The lowerexterior wall 5727 bounds the rear of the club head 5600 below the ledge5825.

FIG. 60 illustrates another cross-sectional view of the golf club head5600, similar to the detailed cross-section of golf club head 5600illustrated in FIG. 56. The internal cavity 5616 comprises a top cavitywidth 5993, a minimum cavity width (minimum gap) 5990, a maximum cavitywidth 6095, and a lower region cavity width 6097, all measured in adirection perpendicular from the strikeface 5612 from an interiorsurface 5819 of the strikeface 5612 to a back edge of the internalcavity 5616. The top cavity width 5993 is located above the minimumupper cavity width 5990. The region of the internal cavity 5616 havingthe greater top cavity width 5993 corresponds to the upper perimeterportion 5609. The portion of the internal cavity 5616 adjacent theminimum upper cavity width 5990 corresponds to the indention 5630. Thetop cavity width 5993 is above the minimum cavity width 5990, which isabove the maximum cavity width 6095, which is above the lower regioncavity width 6097. In some embodiments, the maximum cavity width 5990 islocated in the lower region 5613 of the club head 5600. In manyembodiments, the lower region 5613 of the body 5601 comprises a solidregion adjacent the rear 5610. The solid region provides weighting tothe rear 5610 of the club head 5600. This solid region causes the lowerregion cavity width 6097 to be less than a width of the cavity adjacentand below the indention 5630. The minimum cavity width 5990 can bebetween 20% and 55% of the lower region cavity width 6097 in a centralportion of the club head 5600, such as is shown in the cross-section ofFIG. 60. For example, the minimum cavity width 5990 can be 20%, 25%,30%, 35%, 40%, 45%, or 50% of the lower region cavity width 6097.

The top cavity width 5993 is measured between the rear wall 5723 and aback surface of the strikeface 5612. In some embodiments, top cavitywidth 5993 can range from 0.079 inch (2 mm) to 0.24 inch (6 mm). Forexample, top cavity width can be 0.079 inch (2 mm), 0.118 inch (3 mm),0.16 inch (4 mm), 0.197 inch (5 mm) or 0.24 inch (6 mm). In otherembodiments, top cavity width can range from 0.118 inch (3 mm) to 0.16inch (4 mm). In some embodiments, top cavity width can be 0.135 inch(3.429 mm).

In some embodiments, the minimum cavity width 5990 is located betweenthe first inflection point 5786 and the back surface of the strikeface5612. In some embodiments, the minimum cavity width 5990 is locatedbetween the indention wall 5821 and the back surface of the strikeface5612. In some embodiments, minimum cavity width 5990 can range from0.079 inch (2 mm) to 0.24 inch (6 mm). For example, minimum cavity width5990 can be 0.079 inch (2 mm), 0.118 inch (3 mm), 0.16 inch (4 mm),0.197 inch (5 mm) or 0.24 inch (6 mm). In other embodiments, minimumcavity width 5990 can range from 0.118 inch (3 mm) to 0.16 inch (4 mm).In some embodiments, minimum cavity width 5990 can be 0.135 inch (3.429mm).

The maximum cavity width 6095 is located beneath the indention 5630. Insome embodiments, maximum cavity width 6095 can range from 0.40 inch to0.70 inch. For example, the maximum cavity width can be 0.40 inch, 0.45inch, 0.50 inch, 0.55 inch, 0.60 inch, 0.65 inch, or 0.70 inch. In otherembodiments, maximum cavity width 6095 can range from 0.55 inch to 0.60inch. In some embodiments, maximum cavity width 6095 can be 0.59 inch.

The lower region cavity width 6097 is measured between the solid regionand the interior surface 5819 of the strikeface 5612. In someembodiments, lower region cavity width 6097 can range from 0.15 inch to0.40 inch. For example, the lower region cavity width 6097 can be 0.15inch, 0.20 inch, 0.25 inch, 0.30 inch, 0.35 inch, or 0.40 inch. In otherembodiments, lower region cavity width 6097 can range from 0.27 inch to0.31 inch. In some embodiments, top cavity width can be 0.29 inch.

Referring again to FIG. 60, the body 5601 of golf club head 5600 furthercomprises an upper perimeter portion distance 6092, a minimum distance6094, and a maximum distance 6096. The upper perimeter portion distance6092 of the club head 5600 adjacent to the top rail 5615 is measured asthe perpendicular distance from the exterior surface 5603 of thestrikeface 5612 to the exterior surface 5603 of the rear wall 5623. Theupper perimeter portion distance 6092 of the club head is between 0.305inch and 0.325 inch. In some embodiments, the upper perimeter portiondistance 6092 of the club head is between 0.305 inch and 0.310 inch,0.310 inch and 0.315 inch, 0.315 inch and 0.320 inch, or 0.320 inch and0.325. In some embodiments, the upper perimeter portion distance 6092 ofthe club head 5600 is greater than the ledge width 5829.

The minimum distance 6094 of the body 5601 is measured as theperpendicular distance from the exterior surface 5603 of the strikeface5612 in the upper region 5611 to the exterior surface 5603 of the rearwall 5623. The minimum distance 6094 can range from 0.20 inch to 0.40inch. For example, the minimum distance 6094 can be 0.20 inch, 0.22inch, 0.24 inch, 0.26 inch, 0.28 inch, 0.30 inch, 0.32 inch, 0.34 inch,0.36 inch, 0.038 inch, or 0.40 inch. In some embodiments, the minimumdistance 6094 of the body 5601 can be greater than the ledge width 5829.The maximum distance 6096 of the body 5601 is measured as theperpendicular distance from the exterior surface 5603 of the strikeface5612 to the exterior surface 5603 of the rear 5610. The maximum distance6096 can range from 0.60 inch to 0.90 inch. For example, the maximumdistance 6096 can be 0.60 inch, 0.64 inch, 0.68 inch, 0.72 inch, 0.76inch, 0.80 inch, 0.84 inch, 0.88 inch, or 0.90 inch.

As illustrated in FIG. 58-62, the golf club head 5600 can be a hollow,or at least partially hollow body comprising an internal cavity 5616.Internal cavity 5616 of the body 5601 comprises a volume. The volume ofthe internal cavity 5616 can range from 0.65 inch³ (10.65 cm³) to 1.05inch³ (17.21 cm³). In some embodiments, the internal cavity 5616 cancomprise a volume of 0.65 inch³ (10.65 cm³), 0.70 inch³ (11.47 cm³),0.75 inch³ (12.29 cm³), 0.80 inch³ (13.11 cm³), 0.85 inch³ (13.93 cm³),0.90 inch³ (14.75 cm³), 0.95 inch³ (15.57 cm³), 1.00 inch³ (16.39 cm³),or 1.05 inch³ (17.21 cm³). Similarly, material portion of the body 5601,void of the cavity 5616, further comprises a material volume. Thematerial volume of the body 5601 can range from 2.50 inch³ (40.97 cm³)to 3.50 inch³ (57.35 cm³). For example, the material volume of the body5601 can be 2.50 inch³ (40.97 cm³), 2.60 inch³ (42.61 cm³), 2.70 inch³(44.25 cm³), 2.80 inch³ (45.88 cm³), 2.90 inch³ (47.52 cm³), 3.00 inch³(49.16 cm³), 3.10 inch³ (50.80 cm³), 3.20 inch³ (52.44 cm³), 3.30 inch³(54.08 cm³), 3.40 inch³ (55.72 cm³), or 3.50 inch³ (57.35 cm³).

In many embodiments, the internal cavity 5616 of the body 5601 can bevoid of any substance. In other embodiments, the internal cavity 5616 ofthe body 5601 can comprise a polymer (not pictured), wherein the polymercan be at least partially fill the internal cavity 5616. The polymer canbe polyethylene terephthalate, high-density polyethylene, polyvinylchloride, polycarbonate, polypropylene, other thermoplastics, compositespolymers or any combination thereof. The polymer can fill 10% to 80% 10%to 25%, 15% to 30%, 30% to 45%, 45% to 60%, 60% to 75%, 75% to 80%, 10%to 40%, 30% to 60%, or 40% to 80% of the internal cavity 5616 of thebody 5601. For example, the polymer can fill 10%, 15%, 20%, 25%, 30%,35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or 85% of the internalcavity 5616 of the body 5601. In some embodiments, the polymer fills 80%of the internal cavity 5616 of the body 5601.

The polymer at least partially filling the internal cavity 5616 of thebody 5601 can comprise a specific gravity ranging from 0.05 to 4. Forexample, the specific gravity of the polymer can be 0.5, 1.0, 1.5, 2.0,2.5, 3.0, 3.5, or 4. In some embodiments, the specific gravity of thepolymer is proportional to the mass of the polymer, wherein 1 specificgravity of the polymer is equal to 1 gram. Similarly, in those exemplaryembodiments, the volume is proportional to the polymer specific gravity,wherein 1 specific gravity of the polymer is equal to 1 cc. In otherembodiments, the volume is not proportional to the specific gravity ofthe polymer. For example, the ratio of the polymer specific gravity tothe polymer volume can be 2:1 cc, 2:3 cc, 2:4 cc, 3:1 cc, 3:2 cc, 3:4cc, 4:1 cc, 4:2 cc, or 4:3 cc.

The mass of the polymer allows for the swing weight of the golf clubhead 4400 to be customizable for each player. Increasing the volume ofthe polymer, and thus the mass, increases the swing weight. Similarly,decreasing the volume of the polymer decreases the swing weight. Havingthe appropriate swing weight for each individual player improves feelduring a swing and can improve performance such as swing speed, swingpath, ball speed, and ball trajectory. The polymer can further increasethe overall mass of the golf club head 5600 more toward the sole 5606.Increasing the mass more toward the sole shifts the CG low and back,thereby improves the moment of inertia.

The strikeface 5612 can be coated with a durable finish. For example,the strikeface 5612 can be coated with Hydropearl 2.0 chrome platefinish or a high polished chrome. In some embodiments, the strikeface5612 is further finished with brushing or blasting. The golf club head5600 can further comprise an vibration damping layer 5878 on theinterior surface 5819 of the strikeface 5612. The vibration dampinglayer 5878 can be formed from an elastomer material or any othersuitable material. For example, the vibration damping layer 5878 can beformed from a urethane and graphene coating, a urethane coating, or asilicon gel. The vibration damping layer 5878 can have a weight of 1-7grams. For example, the vibration damping material can have a weight of1 gram, 3 grams, 5 grams, or 7 grams. The vibration damping layer 5878can fill between 10%-30% of the volume of the internal cavity of theclub head 5600. The vibration damping layer 5878 can partially or fullycover the interior surface 5819 of the strikeface 5612. The thickness ofthe vibration damping layer 5878, measured perpendicular to thestrikeface 5612, can either vary or be uniform across the interiorsurface 5819 of the strikeface 5612.

In some embodiments, the golf club head 5600 can further comprise anaperture 5634 located on the toe region 5604. The aperture 5634comprises internal threads and is configured to receive a threaded screwweight 5637, as seen in FIG. 56. FIG. 56 illustrates the threaded screwweight 5637 removed from the aperture 5634 but positioned for insertioninto the aperture 5634. The threaded screw weight 5637 comprises a mass,wherein the mass of the threaded screw weight 5637 can range from 2grams to 12 grams. In other embodiments, the mass of the threaded screwweight 5637 can range from 4 grams to 10 grams. In some embodiments, thescrew weight 5637 can weight 2 grams, 3 grams, 4 grams, 5 grams, 6grams, 7 grams, 8 grams, 9 grams, 10 grams, 11 grams, 12 grams, 13grams, or 14 grams. The mass of the screw weight 5637 correlates withthe length of the screw weight 5637, wherein a longer threaded screwweight 5637 equates to a greater mass. The threaded screw weight 5637further affects the mass and overall swing weight of the golf club head5600. Therefore, the threaded screw weight 5637 can improve the feel ofthe golf club head 5600, as well as performance characteristics (e.g.,swing speed, ball speed, and ball flight).

The hosel of the club head 5600 can house a tip weight 5638. FIG. 56depicts the tip weight 5638 removed from the hosel, but in position forinsertion into the hosel. The tip weight 5638 can have a weight thatranges between 0.1 and 10 grams. For example, the tip weight 5638 canhave a weight of 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10grams.

Although both the toe slit 5666 and heel slit 5662 affect the deflectionof the club head 5600, the toe slit 5666 has a greater effect on thedeflection. The slits 5666, 5662 reduce concentrated stresses at toe andheel junctions between the lower region 5613 and the upper perimeterportion 5609 and spread impact stresses across a greater volume of theclub body 5601. The toe and heel slits 5666, 5662 allow structuralbending between the upper region 5611 and the lower region 5613 of theclub head 5600, which results in greater deflection of the strikeface5612 than would be present in a similar golf club head lacking toeand/or heel slits. The slits 5666, 5662 can increase the bending betweenthe lower region 5613 and the upper region 5611 around the secondinflection point 5792. The greater deflection of the strikeface 5612provides a higher dynamic loft angle to the golf club 5600. The loftangle is an acute angle measured from the strikeface 5612 to a groundreference plane 10. By dynamically increasing the deflection of the clubhead 5600, the conventional loft angle can be lowered withoutsacrificing trajectory. For example, a first club head with a loft anglelower than a second club head can have a trajectory equal to thetrajectory of the second club head if the first club head comprisesslits that increase the deflection of the club head. In someembodiments, the conventional loft angle can be reduced by up to 0.6degrees, up to 0.5 degrees, or up to 0.4 degrees. The lower loft of thefirst club head can result in a higher ball speed for a golf ballimpacted by the club head due to the lower loft angle of the first club.The gapping between clubs in a set can be more uniform in a club headset that comprises the slits disclosed herein.

Furthermore, in many embodiments, indention 5630 can provide an increasein golf ball speed over ball speeds of standard golf club heads and canincrease the launch angle over both the standard hybrid and iron clubheads. A golf club head lacking the indention 5630 cannot buckle in acontrolled manner during impact or spring back like a drum after impactas well as the club head 5600. The first, second, and third inflectionpoints 5786, 5792, and 5794 allow the body 5601 to bend backwards when agolf ball impacts the strikeface in a manner not possible for a golfclub head lacking these inflection points.

The upper perimeter portion can provide spring to the back end of theclub and exhibit low peak stress concentrations. The interaction of thestrikeface 5612, the top rail 5615, the rear wall 5723, and the top wall5719 is affected by the strikeface angle 5950, the top rail angle 5945,and the rear angle 5940. The strikeface 5612, the top rail 5615, therear wall 5723, and the top wall 5719 interact and benefit the hingingof the club head in a manner similar to the respective components ofgolf club head 3700 described above.

The uniform thinned region 6060 on the sole 5606, described above, canprovide multiple benefits, similar to those described above for theuniform thinned regions of golf club heads 2200, 2700, 3200, 3700, 4400,and 4900.

In some embodiments, body 5601 can comprise stainless steel, titanium,aluminum, a steel alloy (e.g. 455 steel, 475 steel, 431 steel, 17-4stainless steel, maraging steel), a titanium alloy (e.g. Ti 7-4, Ti 6-4,T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti 15-5-3, Ti 3-8-6-4-4, Ti10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or any combination thereof), analuminum alloy, or a composite material. In other embodiments, body 5601can comprise carpenter grade 455 steel, carpenter grade 475 steel, C300steel, C350 steel, a Ni—Co—Cr steel alloy, a quench and tempered steelalloy, or 565 steel. In some embodiments, strikeface 4412 can comprisestainless steel, titanium, aluminum, a steel alloy (e.g. 455 steel, 475steel, 431 steel, 17-4 stainless steel, maraging steel), a titaniumalloy (e.g. Ti 7-4, Ti 6-4, T-9S, Ti SSAT2041, Ti SP700, Ti 15-0-3, Ti15-5-3, Ti 3-8-6-4-4, Ti 10-2-3, Ti 15-3-3-3, Ti-6-6-2, Ti-185, or anycombination thereof), an aluminum alloy, or a composite material. Inother embodiments, strikeface 4412 can comprise carpenter grade 455steel, carpenter grade 475 steel, C300 steel, C350 steel, a Ni—Co—Crsteel alloy, a quench and tempered steel alloy, or 565 steel. In someembodiments, body 5601 can comprise the same material as strikeface5612. In some embodiments, body 5601 can comprise a different materialthan strikeface 5612.

III. Golf Club Head with Cascading Sole and Back Cavity

In some embodiments, a golf club head with a back cavity can furthercomprise a cascading sole with tiered thin sections. The cascading solecan be implemented within club heads 2200, 2700, 3200, 3700, 4400, 4900,and 5600. FIG. 14 illustrates a cross-section of golf club head 1100,which can be similar to golf club head 1000 (FIG. 10), along a similarcross-sectional line XII-XII in FIG. 10, according to an embodiment.Similar to golf club head 1000 (FIG. 10), golf club head 1100 comprisesa body 1101. Body 1101 comprises a strikeface 1112, a sole 1106, and acrown 1108. Strikeface 1112 comprises a high region 1176, a middleregion 1174, and a low region 1172. Crown 1108 comprises an upper region1111 and a lower region 1113. The upper region 1111 comprises a top rail1115. In many embodiments, a cavity 1130 is located below top rail 1115.The golf club head 1100 further comprises a cascading sole 1310, similarto internal radius transition 310 (FIG. 3). The internal radiustransition 1310 comprises a first tier 1315 at a first thickness, asecond tier 1317 at a second thickness, and a tier transition region1316. In some embodiments, the cascading sole 1310 can provide furtherpliability to top rail 1115. In many embodiments, the back cavitycombined with the cascading sole can provide an even greater springeffect on the strikeface. In some embodiments, the back cavity with thecascading sole allows approximately 3%-5% more energy in the deflectionof the strikeface. The cascading sole 1310 can include any number oftiers greater than or equal to two tiers. For example, the cascadingsole 1310 can have 2, 3, 4, 5, 6, or 7 tiers.

The golf club head 1100 (in some embodiments, club heads 2200, 2700,3200, 3700, 4400, 4900, and 5600) having the cascading sole and the backcavity can provide a greater recoiling force to the strikeface than thegolf club head having the cascading sole or back cavity alone. This isdue to the combined increased recoiling force from both the internalradius transition and the back cavity, as discussed above. The increasedrecoiling force to the strikeface leads to greater deflection, which inturn increases the impact force applied to the golf ball therebyincreasing the speed of the golf ball. In some embodiments, golf clubhead 1100 comprising both cavity 1130 and internal radius transition1310 can increase ball speed, increase launch angle, and provide betterdistance control. In various embodiments, golf club head 1100 canincrease ball speeds approximately 1% to approximately 4%. In someembodiments, golf club head 1100 can increase ball speeds approximately1%, 2%, 3%, or 4%. In many embodiments, golf club head 1100 provides alarger increase in ball speeds when the golf ball impacts the strikefacein high region 1176. In some embodiments, golf club head 1100 canincrease the launch angle by approximately 0.5 degrees to approximately1.1 degrees. In some embodiments, golf club head 1100 can increase thelaunch angle by approximately 0.5 degrees, 0.6 degrees, 0.7 degrees, 0.8degrees, 0.9 degrees, 1.0 degrees, or 1.1 degrees.

An embodiment of golf club head 1100 having the cascading sole and theback cavity was tested. Overall, when compared to a control golf clubhead devoid of the cascading sole and the back cavity, the cavity golfclub head showed an increase in golf ball speed and an increase inlaunch angle. The cavity golf club head showed the increase in golf ballspeed and the increase in launch angle for all contact positions on theface due to the combined spring effect from the combination of cascadingsole 1310 (FIG. 14) and cavity 1130 (FIG. 14). In some embodiments, agreater increase in golf ball speed and launch angle was observed oncontact with high portions of the face, (e.g., high region 1076 (FIG.12) or high region 1176 (FIG. 14)) due in part from the spring effect ofcavity 1130 (FIG. 14). FIGS. 19-20 depict results from the testing ofthe embodiment of golf club head 1100 (cavity golf club head) comparedto a standard iron-type golf club head (control golf club head) with aclosed back design and similar loft angle as the cavity golf club head.FIG. 19 shows an increase in golf ball speed in the cavity golf clubhead compared to the control golf club head when the golf ball impactsthe high region of the strikeface, and FIG. 20 shows an increase inlaunch angle of the cavity golf club head compared to the control golfclub head when the golf ball impacts the high region of the strikeface.

Specifically, FIG. 19 shows that golf ball speed is increased byapproximately 1.9% (or approximately 2.5 mph) for the cavity golf clubhead when the golf ball impacts a high-toe region of the strikeface,approximately 2.1% (or approximately 2.8 mph, or approximately 4.5 kph)when the golf ball impacts a high-center region of the strikeface, andapproximately 1.5% (or approximately 2.0 mph, or approximately 3.2 kph)when the golf ball impacts a high-heel region of the strikeface (all ofthe cavity golf club head), when compared to the control golf club head.When the golf ball impacts the strikeface in the high-toe region of thecontrol golf club head, the golf ball speed is approximately 132.5 mph(213.2 kph), while the golf ball reaches approximately 135.0 mph (217.3kph) when it impacts the strikeface in the high-toe region of the cavitygolf club head. When the golf ball impacts the strikeface in thehigh-center region of the control golf club head, the golf ball speed isapproximately 133.4 mph (214.7 kph), while the golf ball reachesapproximately 136.2 mph (219.2 kph) when it impacts the strikeface inthe high-center region of the cavity golf club head. When the golf ballimpacts the strikeface in the high-heel region of the control golf clubhead, the golf ball speed is approximately 134.0 mph (215.7 kph), whilethe golf ball reaches approximately 136.0 mph (218.9 kph) when itimpacts the strikeface in the high-heel region of the cavity golf clubhead.

FIG. 20 shows that launch angle of the cavity golf club head isincreased by approximately 4.2% (or approximately 0.6 degrees) when thegolf ball impacts the high-toe region of the strikeface, approximately4.8% (or approximately 0.7 degrees) when the golf ball impacts thehigh-center region of the strikeface, and approximately 6.4% (orapproximately 0.9 degrees) when the golf ball impacts the high-heelregion of the strikeface (all of the cavity golf club head), whencompared with the control golf club head. When the golf ball impacts thestrikeface in the high-toe region of the control golf club head, thelaunch angle is approximately 14.4 degrees, while the launch angle isapproximately 15.0 degrees when it impacts the strikeface in thehigh-toe region of the cavity golf club head. When the golf ball impactsthe strikeface in the high-center region of the control golf club head,the launch angle is approximately 14.5 degrees, while the launch angleis approximately 15.2 degrees when it impacts the strikeface in thehigh-center region of the cavity golf club head. When the golf ballimpacts the strikeface in the high-heel region of the control golf clubhead, the launch angle is approximately 14.1 degrees, while the launchangle is approximately 15.0 degrees when it impacts the strikeface inthe high-heel region of the cavity golf club head.

FIG. 17 illustrates method 1700 for manufacturing a golf club head.Method 1700 comprises providing a body (block 1705). Providing a body inblock 1705 comprises the body having a strikeface, a heel region, a toeregion opposite the heel region, a sole, and a crown. In manyembodiments, the crown comprises an upper region and a lower region. Insome embodiments, the upper region comprises a top rail. In manyembodiments, a cavity is located below the top rail and is located abovethe lower region of the crown (block 1710). In some embodiments, thecavity is defined at least in part by the upper and lower regions of thecrown. The cavity comprises a top wall, a back wall adjacent to the topwall, a bottom incline adjacent to the back wall, a back cavity anglemeasured between the top and back walls of the cavity, and at least onechannel.

In some embodiments, method 1700 further comprises providing an insertat the lower region of the crown towards the toe region. In someembodiments, the insert is similar to insert 1062 (FIG. 10).

In some embodiments, providing the body in block 1705 further comprisesthe body having a cascading sole. The cascading sole comprises aninternal radius transition region from the strikeface to the sole. Inmany embodiments, the internal radius transition region can be similarto internal transition region or cascading sole 1310 (FIG. 14). In someembodiments, the internal transition region comprises a first tiercomprising a first thickness, a second tier comprising a secondthickness smaller than the first thickness, and a tier transition regionbetween the first tier and the second tier.

IV. Golf Club with Cascading Sole and Back Cavity

Turning to FIG. 15, FIG. 15 illustrates a golf club 1500 comprising agolf club head 1500 and a shaft 1590 coupled to golf club head 1500. Insome embodiments, golf club head 1500 of golf club 15000 comprises ahybrid-type golf club head. In other embodiments, golf club head 1500can be an iron-type golf club head or a fairway wood-type golf clubhead. In many embodiments, golf club head 1500 can be similar to golfclub head 100 or golf club head 1000 (FIG. 10). Golf club head 1500 canbe hollow-bodied and comprises a strikeface 1512, a heel region 1502, atoe region 1504 opposite heel region 1502, a sole 1506, and a crown1508. The crown 1508 comprises an upper region 1511 and a lower region1513. The upper region 1511 comprises a top rail 1515. Golf club head1500 further comprises a cavity 1530 located below top rail 1515 andabove lower region 1513 of crown 1508.

FIG. 16 illustrates a cross-section of golf club head 1500 along thecross-sectional line XVI-XVI in FIG. 15, according to one embodiment. Insome embodiments, cavity 1530 can be defined at least in part by upperregion 1511 and lower region 1513. In many embodiments, cavity 1530comprises a top wall 1517, a back wall 1519, a bottom incline 1521, aback cavity angle 1535 measured between top wall 1517 and back wall1519, and at least one channel 1539. In some embodiments, an apex of topwall 1517 is approximately 0.25 inch to approximately 1.25 inches belowan apex of top rail 1515. In some embodiments, the apex of top wall 1517is approximately 0.375 inch below the apex of top rail 1515. In someembodiments, bottom incline 1521 can be at least approximately 0.50 inchto approximately 2 inches below an apex of top rail 1515. In manyembodiments, back cavity angle 1535 can be approximately 70 degrees toapproximately 110 degrees. In some embodiments, back cavity angle 1535can be approximately 90 degrees.

In many embodiments, the upper region 1511 comprises the top and backwalls of the cavity; and the lower region of the crown comprises thebottom incline of the cavity. In some embodiments, upper region 1511further comprises a rear wall 1523 adjacent to top wall 1517 of cavity1530 and a rear angle 1540 measured between top wall 1517 of cavity 1530and rear wall 1523 of upper region 1511. In many embodiments, rear angle1540 is approximately 70 degrees to approximately 110 degrees.

In another embodiment, the golf club head can comprise a hosel. Thehosel can comprise a hosel notch. The hosel notch can allow foriron-like range of loft and lie angle adjustability. Although notillustrated in FIG. 16, golf club head 1500 also can have a cascadingsole or an internal radius transition at the sole.

The golf club heads with energy storage characteristics discussed hereinmay be implemented in a variety of embodiments, and the foregoingdiscussion of these embodiments does not necessarily represent acomplete description of all possible embodiments. Rather, the detaileddescription of the drawings, and the drawings themselves, disclose atleast one preferred embodiment of golf club heads with energy storagecharacteristics, and may disclose alternative embodiments of golf clubheads with tiered internal thin sections.

EXAMPLES Example 1: Cavity Back Vs. Hollow Body/Inflection Point GolfClub

Referring to Table 1 below, the exemplary club head 3700 being a hollowbodied iron club head with an inflection point 3986 was compared to twocontrol club head (hereafter “Control 1” and “Control 2”). Control 1 andControl 2 were cavity back iron club heads that were similar in size andloft angle to exemplary club head 3700, but were devoid of an inflectionpoint. Control 2 has a more pronounced cavity and wider sole thanControl 1. Ball speed (measured in mph), launch angle (measured indegrees), carry distance (measured in yards), and spin rate (measured inrpm) were measured between the exemplary club head 3700, Control 1, andControl 2.

TABLE 1 Performance of Club Head 3700 vs. Control Club Heads 1 and 2Average Average Average Average Carry Ball Speed Launch Angle Spin RateDistance (mph) (degrees) (rpm) (yards) Club Head 3700 127.3 15.9 5931193 Control 1 127.6 15.4 5972 190 Control 2 126.3 15.8 6551 185

As shown in Table 1, the exemplary club head 3700 having a hollow bodyand inflection point 3986 produced an average ball speed of 127.3 mph,an average launch angle of 15.9 degrees, an average carry distance of193 yards, and an average spin rate of 5931 rpm. Comparatively, Control1 produced an average ball speed of 127.6 mph, an average launch angleof 15.4 degrees, an average carry distance of 190 yards, and an averagespin rate of 5972 rpm, and Control 2 produced an average ball speed of126.3 mph, an average launch angle of 15.8 degrees, an average carrydistance of 185 yards, and an average spin rate of 6551 rpm. Althoughthe exemplary club head 3700 experienced a decrease of about 0.2% inaverage ball speed compared to Control 1 and an increase of about 0.8%to 1% in average ball speed compared to Control 2, the average launchangle and average spin rate increased the average carry distance fartherdue to the hollow body and inflection point 3986 of the exemplary clubhead 3700. The exemplary club head 3700 experienced a 3.25% increase inthe average launch angle compared to Control 1, and a 0.6% to 1%increase in the average launch angle compared to the Control 2respectively. Further, the exemplary club head 3700 experienced around a0.7% decrease in average spin rate compared to Control 1 and a 9.46%decrease in average spin rate compared to Control 2 respectively. Theincreased average launch angle and decreased average spin rate of theexemplary club head 3700 compared to the Control 1 and 2 increased thecarry distance of the ball during impact. More specifically, theexemplary club head 3700 experienced a 1.58% compared to Control 1 and4.32% increase in average carry distance of the ball compared to Control1 and Control 2. Therefore, the hollow body and inflection point 3986 ofthe exemplary club head 3700 increases the bending of the strikeface3712 to produce optimal ball performance characteristic compared tosimilar sized club heads devoid of an inflection point.

Example 2: Cavity Back Vs. Hollow Body/Inflection Point Golf Club

Referring to Table 2 below, the exemplary club head 4400 being a hollowbodied iron club head with an inflection point 4686 that is 55% from thetop rail apex to the inflection point of the club head 4400 was comparedto a control club head (hereafter “Control Club Head”). Control ClubHead was a cavity back iron club head similar in size and loft angle toexemplary club head 4400, but devoid of an inflection point and hollowbody. Similar to Table 1 above, the parameters measured to compare theexemplary club head 4400 and the Control Club Head were as follows: ballspeed (measured in mph), launch angle (measured in degrees), carrydistance (measured in yards), and spin rate (measured in rpm).

TABLE 2 Performance of Club Head 4400 vs. Control Club Head AverageAverage Average Average Carry Ball Speed Launch Angle Spin Rate Distance(mph) (degrees) (rpm) (yards) Club Head 4400 123.8 16.8 6211 179.2Control 1 123.3 16.1 6746 175.7

As shown in Table 2, the exemplary club head 4400 having a hollow bodyand inflection point 4686 produced an average ball speed of 123.8 mph,an average launch angle of 16.8 degrees, an average carry distance of179.2 yards, and an average spin rate of 6211 rpm, compared to theControl Club Head which produced an average ball speed of 123.3 mph, anaverage launch angle of 16.1 degrees, an average carry distance of 175.7yards, and an average spin rate of 6746 rpm. The exemplary club head4400 experienced a 0.5-1% increase in ball speed compared to the ControlClub Head, but due to the hollow body and inflection point 4686 whichincreased the bending of the strikeface 4412, the exemplary club head4400 experienced a 4.35% increase in the launch angle and a 7.93%decrease in the spin rate. Because of the 4.35% increase in the launchangle and 7.93% decrease in spin rate, the exemplary club head 4400experienced an increase of around 2% of the carry distance farther thanthe Control Club Head. Therefore, this increase in bending of thestrikeface 4412 due to the hollow body and inflection 4686 of theexemplary club head 4400 allows for farther carry distances of the ballcompared to club head similar in size, devoid of an inflection point.

Example 3: Smaller Volume Hollow Body Irons Vs. Hollow Body Crossover

Referring to Table 3 below, the exemplary club head 3700, and exemplaryclub head 4400 were compared to exemplary club head 2700. All threeexemplary club heads 3700, 4400, and 2700 had similar loft angles andcomprised a hollow body, and an inflection point. Exemplary club heads3700 and 4400 are both significantly smaller in size (volume rangingfrom 0.65 inch³ to 1.70 inches³) than the exemplary club head 2700(volume around 1.75 inches³). Similar to Table 1 and Table 2 above, theparameters measured for the exemplary club heads 3700, 4400, and 2700are ball speed (measured in mph), launch angle (measured in degrees),carry distance (measured in yards), and spin rate (measured in rpm).

TABLE 3 Performance of Club Head 3700 and Club Head 400 vs. Club Head2700 Average Average Average Average Carry Ball Speed Launch Angle SpinRate Distance (mph) (degrees) (rpm) (yards) Club Head 3700 138.8 12.24322 219 Club Head 4400 138.0 11.4 4135 216 Club Head 2700 139.3 11.84312 217

As shown in Table 3, the exemplary club head 3700 produced an averageball speed of 138.8 mph, an average launch angle of 12.2 degrees, anaverage spin rate of 4322 rpm, and an average carry distance of 219yards; the exemplary club head 4400 produced an average ball speed of138.0 mph, an average launch angle of 11.4 degrees, an average spin rateof 4135 rpm, and an average carry distance of 216 yards; and theexemplary club head 2700 produced an average ball speed of 139.3 mph, anaverage launch angle of 11.8 degrees, an average spin rate of 4312 rpm,and an average carry distance of 217 yards. The exemplary club head 3700experienced a 0.92% increase in carry distance over the exemplary clubhad 2700, while the exemplary club head 4400 experienced a 0.46%decrease in carry distance compared to the exemplary club had 2700. Thesmall percent difference of the carry distance of the ball between theexemplary club heads 3700, 4400, and 2700, were indicative to thebending of the strikeface due to the hollow body and inflection points,regardless of the significantly smaller sizes of the exemplary club head3700 and exemplary club head 4400. Because of the smaller size and lowerinflection point, the exemplary club heads 3700 and 4400 allows a playerthe benefit of the look and feel of a smaller iron body club head, withthe ball performance results (e.g., launch angle, carry distance) of ahigher volume sized hollow body club head with a higher inflection point(i.e., exemplary club head 2700).

Example 4: Cavity Back Vs. Hollow Body/Inflection Point Golf Club

Referring to Table 4 below, the exemplary club head 4900 is a hollowbodied iron club head with an inflection point 5186 located roughly 52%below the top rail apex. The club head 4900 was compared to a controlclub head (hereafter “Control Club Head”). Control Club Head was acavity back iron club head similar in size to exemplary club head 4900,but devoid of an inflection point and hollow body. The Control Club Headcomprised a loft angle roughly 1° lower than the exemplary club head4900. Similar to Table 1 above, the parameters measured to compare theexemplary club head 4900 and the Control Club Head were as follows: ballspeed (measured in mph), launch angle (measured in degrees), carrydistance (measured in yards), and spin rate (measured in rpm).

TABLE 4 Performance of Club Head 4900 vs. Control Club Head AverageAverage Average Average Carry Ball Speed Launch Angle Spin Rate Distance(mph) (degrees) (rpm) (yards) Club Head 4900 145.1 11.6 3980 229 Control1 146.1 11.1 4073 227

As shown in Table 2, the exemplary club head 4900 having a hollow bodyand inflection point 5186 produced an average ball speed of 145.1 mph,an average launch angle of 11.6 degrees, an average carry distance of229 yards, and an average spin rate of 3980 rpm, compared to the ControlClub Head which produced an average ball speed of 146.1 mph, an averagelaunch angle of 11.1 degrees, an average carry distance of 227 yards,and an average spin rate of 4073 rpm.

The higher launch angle of the club head 4900 results from its higherloft angle. The lower ball speed can also be expected due to the higherloft angle of the club head 4900. The unexpected result is in the spinrate of the club head 4900 versus the spin rate of the Control ClubHead. One of skill in the art would expect the spin rate of thehigher-lofted club head (in this example the club head 4900) to besignificantly greater than the spin rate of the lower-lofted club head(in this example the Control Club Head). However, the measured spinrates are close to each other, to the extent that in the measured data,the error bars of the spin rates overlap. The spin rates of the clubhead 4900 and the Control Club Head are not significantly different.Thus, this test shows that the golf club head 4900 exhibits lower spinrates than the Control Club Head for a given loft angle. This lower spinrate reduces the ballooning of the golf ball during flight. Golf ballsthat are imparted a high spin rate upon impact tend to twist upwards, orballoon, during flight. This dynamic increase in the flight trajectoryheight of the golf ball can adversely affect the carry distance andresult in unpredictable shots. The average carry distance for theexemplary golf club 4900 is roughly the same as the average carrydistance of the Control Club Head. The inflection point 5186 of theexemplary club head 4900 along with the hollow body allow the faceplate4912 to bend in a manner that reduces the spin imparted to the golfball.

In addition to the data in Table 4 above, the test revealed an averagestatistical plot area within which the test shots landed. The averagestatistical plot area for the exemplary club head 4900 was 6.2% smallerthan the average statistical plot area for the Control Club Head. Thisshows that the exemplary club head 4900 demonstrated higher precisionthan the Control Club Head. Therefore, the hinging of the faceplate 4912about the inflection point 5186 does not adversely affect the golfer'sability to control their shots. Rather, the golfer's shot precision isincreased.

Replacement of one or more claimed elements constitutes reconstructionand not repair. Additionally, benefits, other advantages, and solutionsto problems have been described with regard to specific embodiments. Thebenefits, advantages, solutions to problems, and any element or elementsthat may cause any benefit, advantage, or solution to occur or becomemore pronounced, however, are not to be construed as critical, required,or essential features or elements of any or all of the claims, unlesssuch benefits, advantages, solutions, or elements are expressly statedin such claims.

As the rules to golf may change from time to time (e.g., new regulationsmay be adopted or old rules may be eliminated or modified by golfstandard organizations and/or governing bodies such as the United StatesGolf Association (USGA), the Royal and Ancient Golf Club of St. Andrews(R&A), etc.), golf equipment related to the apparatus, methods, andarticles of manufacture described herein may be conforming ornon-conforming to the rules of golf at any particular time. Accordingly,golf equipment related to the apparatus, methods, and articles ofmanufacture described herein may be advertised, offered for sale, and/orsold as conforming or non-conforming golf equipment. The apparatus,methods, and articles of manufacture described herein are not limited inthis regard.

While the above examples may be described in connection with adriver-type golf club, the apparatus, methods, and articles ofmanufacture described herein may be applicable to other types of golfclub such as a fairway wood-type golf club, a hybrid-type golf club, aniron-type golf club, a wedge-type golf club, or a putter-type golf club.Alternatively, the apparatus, methods, and articles of manufacturedescribed herein may be applicable to other type of sports equipmentsuch as a hockey stick, a tennis racket, a fishing pole, a ski pole,etc.

Moreover, embodiments and limitations disclosed herein are not dedicatedto the public under the doctrine of dedication if the embodiments and/orlimitations: (1) are not expressly claimed in the claims; and (2) are orare potentially equivalents of express elements and/or limitations inthe claims under the doctrine of equivalents.

What is claimed is:
 1. A hollow golf club head comprising: a strike faceand a rear wall opposite the strikeface; a sole and a top rail oppositethe sole; a plurality of ribs extending in a direction from the top railto the sole; wherein the strikeface, rear wall, sole, and top railcooperate to define a closed internal volume therebetween; wherein therear wall comprises an upper rear wall and a lower rear wall; whereinthe upper rear wall directly abuts the top rail, and the lower rear walldirectly abuts the sole; and wherein the top rail comprises a thicknessbetween 0.04 inch and 0.08 inch.
 2. The hollow golf club head of claim1, wherein: a lower rear wall comprises a bottom incline and a lowerexterior wall; the hollow golf club head further comprises: a firstinflection point defining a junction between the upper rear wall and thelower rear wall; a second inflection point defining a junction betweenthe bottom incline and the lower exterior wall; a lower angle measuredfrom between the bottom incline and the lower exterior wall, the lowerangle is less than 180 degrees; and an inflection angle measured fromthe upper rear wall to the bottom incline, the inflection angle between95 degrees and 150 degrees.
 3. The hollow golf club head of claim 1,wherein: a lower rear wall comprises a bottom incline and a lowerexterior wall; the hollow golf club head further comprises: a firstinflection point defining a junction between the upper rear wall and thelower rear wall; and a second inflection point defining a junctionbetween the bottom incline and the lower exterior wall; the upper rearwall comprises a thickness between 0.04 inch and 0.08 inch; the rearwall at the first inflection point comprises a thickness between 0.04inch to 0.08 inch; and the thickness of the rear wall at the firstinflection point is less than a thickness of the bottom incline.
 4. Thehollow golf club head of claim 1, wherein a thickness of the rear wallequals the thickness of the top rail.
 5. The hollow golf club head ofclaim 2, wherein the bottom incline comprises a length measured from thefirst inflection point to the second inflection point, the bottomincline length between 0 inch to 0.55 inch.
 6. The hollow golf club headof claim 1, wherein the upper back wall is substantially parallel to thestrikeface.
 7. The hollow golf club head of claim 1, wherein: the hollowgolf club head further comprises a first inflection point defining ajunction between the upper rear wall and the lower rear wall; the upperback wall comprises a height measured from the first inflection point toan apex of the top rail, the height of the upper back wall between 0.6inch and 1.2 inch.
 8. The hollow golf club head of claim 1, wherein: thehollow golf club head further comprises a first inflection pointdefining a junction between the upper rear wall and the lower rear wall;the hollow golf club head comprises a height, measured parallel to thestrikeface from the sole to the top rail; and the upper back wallcomprises a height measured from the first inflection point to an apexof the top rail, the height of the upper back wall between 40% to 75% ofthe height of the hollow golf club head.
 9. The hollow golf club head ofclaim 1, wherein the plurality of ribs comprises between one and eightribs.
 10. The hollow golf club head of claim 1, wherein the plurality ofribs comprises at least three ribs.
 11. The hollow golf club head ofclaim 1, wherein the plurality of ribs are spaced equidistant from eachother.
 12. The hollow golf club head of claim 1, wherein the pluralityof ribs is positioned on an interior surface of the rear wall.
 13. Thehollow golf club head of claim 1, wherein the hollow golf club headfurther comprises a polymer material that at least partially fills theclosed internal volume.
 14. The hollow golf club head of claim 13,wherein the polymer material comprises a weight between 2 grams and 7grams.
 15. The hollow golf club head of claim 13, wherein the polymermaterial comprises a specific gravity between 0.05 and 4.00.